Got a new idea today and begun to put it into action. As many of you know, winter is cold in Wisconsin, too cold for fish to grow. So I decided to attempt to over winter a few test fry in a 55 gallon aquarium and release them in spring. I plan on this increasing growth of the fry compared to their pond counterparts. I have already captured 7 tests subjects and I just hope the damn angelfish don't eat them.

Any suggestions or ideas?

Bloodworms and hydrated pellets. You can run pellets through a coffee bean grinder if needed for smaller crumbles to get them started. I like to put pellet crumbles in a wire mesh strainer and shake it back and forth to clean out the dust and small peices. Your angle fish might end up hogging the food though.

Thanks I'll see if I can find some.

In an aquarium setting my preference is to get them on a diet formulated for cichlids. Starting size of fish is important and potentially a major challenge if even large breeder angels can eat them. Post a picture so we can we condition.

Hand-paint BG I started with back in July were at least 2" and in good weight so could go straight on a carnivore cichlid pellet. Some smaller fry less than 1" and good health got a short pulse of freeze dried blood worms before going on to small granules. Shorty's hydration approach works very well. When I hydrate pellets only enough water needed to make the moist is used and it made fresh daily. I have a plastic eye-dropper to mix the feed and transfer it to tank.

If your fish are in poor condition, then consider using some super tasty like freeze-dried krill (ground) or frozen blood worms. Really poor condition fish might even better be treated with freshly hatched baby brine shrimp.

This week I will feed training some Coppernose BG, maybe we can compare notes. Mine are still on live baby brine shrimp.


If fish do even half descent then they could be pushing 6" by spring.

When the BG get about 3.5" - 4", they will nip the fins off the angelfish.

Attached some pics of food and a few of the fry. Not 100% sure that they are BG but it doesn't matter but guesses are welcome. Is the food I have good enough? Fry are about 1 inch long.
Also, I'd like to know any ideas to separate the tank. As in, when the BG get too big and start harassing the other fish I'd like to do something. I was thinking some sort of net to cut the tank in half. Ideas?


Plan can always be aborted for the next month ish.

Personally, I would put the BG in a tank by themselves, 100 gallon or larger, and, if it's in the house, it won't need a heater in the winter if you keep the house at about 67-68 degrees or more.

Great idea but another tank is not an option for me. If you think splitting the tank won't work that's ok I'll just put them back.

You can relatively divide a 55-gallon aquarium using egg crate lens material cut to fit. I would divide tank in half. To suppress social problems, stock more bluegill. I can keep forty 4" BG in a 55-gallon assuming aggressive filtration and frequent water changes. Keeping density high will suppress breeding issues when temperature maintenance for anglefish realized. Bluegill will get urge to breed even during winter if temperature and photoperiod appropriate.

Your sunfish are Green Sunfish. Care regimen same except for jumping issues later. Feeds OK but get fish onto pellets of similar brands quickly. Flake feeds and dried insect are a lot of buck for you bang.

Alright, so if I understand you correctly, separate the tank with egg crate, put more BG/SF in, get pellet food to feed them, and clean the tank often.
Also, I don't quite understand, do you mean more BG will stop breeding or stop stress from not being able to breed?

I'm not surprised that they are GSF but I'll hope at least one of them is a BG or a PS.

Thanks for the help.

Get them on feed of any sort that it not live, then get them onto pellets. Pellets can be your start if feed training goes well. Aggressive water quality management needed as I keep my sunfish when shooting for growth without reproduction.


Successful reproduction is not needed to complicate tank culturing sunfish. When fish are in good condition, temperature is between 72 F and 82 F, and photoperiod is has more than 14 hour light per 24-hour cycle it is hard to keep BG, Green Sunfish and PS from feeling the need to breed. I have bred many sunfish species in aquariums and ponds and it is too easy. So much so as to be problematic.

Several approaches can be used to suppress breeding. One is sorting fish by sex which your fish are still too small to do visually. Another is maintaining stocking density so high males cannot establish their nesting territories from which they launch attacks on tank mates. More fish in relatively tight confines also works to suppress formation of hierarchy. I have a dozen 75-gallon tanks where each is loaded with either BG, Green Sunfish, or F1 Green Sunfish x Orange Spotted Sunfish. Fish range in length from 3 to 5 inches. Stocking density is pushed to fish cannot single out a tank mate because they can recognize it. The sunfish are like chickens, they can remember only so many faces, thereafter they slip into a schooling mode where aggression is less of an issue.

Catch a bunch and lay them in shallow water in white container, then photograph. We may be able to find PS and BG that way.

Found this fish food online. Seems to be the only one I'll have access to easily. It is 36% protein.

Will attempt to capture a few more today. Also will be cleaning the tank so I have the option to separate the fry from the other fish. I should have mentioned earlier that there are other smaller minnows in the tank that will be vulnerable to the BG as they get bigger.
How many is enough? Should I shoot for 15, 20, more?

I have overwintered a small number of RES in an aquarium several times and never had them attempt to breed. I have kept the water temps around 70 degrees and the aquarium lights set on a maximum 12 hour run (photo period).

I would check a Pet store for frozen bloodworms and small cichlid pellets to get started. I like to use a shot glass and a little bit of aquarium water to thaw the bloodworms before putting them in the tank. Sunfish really go nuts over bloodworms and it is a good way to get them used to being fed, start feeding them hydrated pellets as soon as you can.

The aquarium grade fish feeds with 36% crude protein and other wire formulated for either carnivore or omnivore will do fine. Twenty fish started at about 1" also good.

Shorty, to get a different experience with the RES bump up temperature and photoperiod. Also provide a little live eats like meal worms making so fish starting coming up to your hands. That level of tameness help acclimate fish to tank so they more completely settle in.

Added 9 more fry today. Caught 1 big 2-3 inch fingerling but I put him in a cage so he wouldn't eat the other fish. May release him but that shows how good my YOY growth rates are. Grand total excluding the fingerling now is 16 fry. I may stop here as this is a good enough number for me.

Picture a wee bit fuzzy for good ID. Biggest and at least several others Green Sunfish. You may have a PS or two. None scream BG to my eyes.


To facilitate ID, I place fish in a flat pan with just enough water to cover them while they are laying on their sides. It keeps several in focus at same time.

RES go nuts on bloodworms poured out of a shot glass which will acclimate them to the tank and get them feeding right away. The ones out in my shop were feeding vigorously within two hours of being put in tbe tank and it was a two hour drive home to get them here. I have been keeping water temps out in my shop tank at 80 degrees all summer. I also use a shot glass to dip a little tank water to hydrate feed daily. I actually had a small 2" RES jump into the glass earlier this summer while getting water to hydrate feed. I also have to watch my fingers at the surface of the tank as they swarm and nibble. Occasionally I'll have a 4" to 5" RES jump out hit my finger as I'm dropping hydrated pellets on the surface. Daily tank cleaning along with a water change has made them very tame.

That is what I strive for when tank spawning. The fish show little or no fear even while I loom over tank. Try adding a bowl 2/3 filled with gravel into corner of tank. Size bowl so diameter 1.5X diameter of largest male.

Can you sex the RES by looking at them?

I am pretty sure that I can, I would have to pull them out and get a good look at them individually to be sure, anything over 5" should be easy to sex. I do know that the single largest RES (7"+) in the tank is female. I looked her over good when I moved them into a bigger a tank back in July when she was 5". All of these were 1-1/2" to 2" when I picked them up in May with the exception of one 3" RES which is now the 7" female I mentioned above. I do have a 75 gallon tank in the house that I can overwinter a few RES in.

You have much needed to do a little overwinter breeding. Can you partition off about 1/3 of tank for largest and most intensely colored male? Prior to actual breeding mode I look for bright red opercular tabs.

See following.

http://www.nanfa.org/articles/pdf/BantamSunfishspawning.pdf


My undergraduate student led second effort.
http://www.nanfa.org/articles/pdf/Warmouthspawning.pdf



BG, RES, GSF, and PS are the same in a tank setting.

Night time update
I have released the large GSF due to stress it may cause other fish and I'd prefer to have more similarly sized fish.
I have at least 1 fry eating flakes so far. He is the largest and healthiest of the bunch. The other fry are oblivious to feeding time.

Is there a way to get them to eat? I assume they will get better with time and size. It may be because they are under transplant stress and will get smart and feed over time.

Seeing one tank mate will be a strong motivator. Assuming fish where not too dinged during capture and introduction process, they will come on to feed within a day or so. Green Sunfish, PS, and BG have been the easiest natives for me to feed train.

I like to apply small amounts multiple times per day. Fish I keep in home are trained by popping with food as soon as I get up, just before going of to work, after getting home and couple more times before going to bed. Having light on at all times during feed training is typical way I do it indoors, otherwise the complete darkness realized indoors causes stress in its own right.

Amount of feed applied is not enough to consume in five minutes. Rather it needs to be gone in 30 seconds or less. Consider blocking direct light over section of tank housing your sunfish until feed training complete.

Since many are Green Sunfish, start thinking about how to prevent jumping from tank if lid is not already tight.

I do have a decently secure lid. It may not be able to completely prevent fry from jumping but as they get bigger all holes are too small.
I'm hoping my tropical fish can help teach the fry although they were never good about eating either.
Thank you for all the help.

Morning update.
Just feed the fish. Many more fry began to eat. They displayed distaste towards flakes, spitting them out, but loved the freeze dried blood worms. The 1 that started to eat immediatly taught at least a quarter of the others. This is a step in the right direction.

Keep with providing flakes. Flakes complete while dried bloodworms are probably not. You can also mix the two immediately prior to feeding. We call that co-feeding.

Will likely take a couple of days before satiation involves actual gut fill. Gut fill needed for good growth.

Fry still alive and growing albeit slowly. They are on the cusp of being fry now, nearly a week behind full siblings of same brood being kept indoors.

I couple dragonfly nymphs also present and likely getting a couple of the fish. Midges likely dominated the dragonfly's fare. Still too many fish as they will over run forage base soon. Need to cull about three quarters of them as all I want is between 10 and 20. This late summer has been exceptional for the tank water temperature. Normally temperatures would consistently be in the lower 60's by now yet we are staying in the upper 60's to lower 70's. Still below optimal.


I did not intend to post this here.

How about an indoor brood vs outdoor brood pic at same age?

Quick update
Fry eating very well. Have gotten one to eat out of my hand. They are a lot more used to flakes now and almost all will readily consume flakes. Ravenous little buggers don't let the blood worms hit the water anymore.

Some time has passed so I'd like to give an update.

Fish are feeding well and growing fast. I swear they are bigger every morning. Only 1 mortality because it never caught on to eating. Pretty sure they are all GSF at this point which is not a problem. So I come to my question, most of the fish are the same green color but 1 or 2 are significantly darker, looking more blue than green. I have seen this before in GSF but why does it happen? They live in the same place. Is it gender or a genetic thing? Thanks.

Now you are in the middle of how I live. The color changes can be a function of social interaction. Your photograph rivals mine in not depicting what you are describing. The fish can change coloration in seconds. Are the darker fish generally smaller and possibly positioning themselves away from larger, possibly aggressive fish?

Looks like I will be breeding some combination of Green Sunfish, Warmouth and Bluegill come January with 4H youth doing aquaculture projects. This may promote some replication of what you are seeing. We already have several 75-gallon aquariums with Green Sunfish so I might be able to look and see if something similar is going on and can be photographed.

Darn dog just unplugged my computer!

Can't photograph color differences because I have to turn the light on to get a picture and the fish immediatly lose their color. I'll try something different tonight. The darker fish are medium-large comparatively and are rather aggressive.

Do the aggressive fish exhibit a dark spot on the posterior part of dorsal and possibly anal fins? Also look at eyes and opercular tabs.


I am in lab now and will try to setup to photograph what mine do. Background color might be an issue. Aggressive fish often try to maximize contrast with background.

Not even sure this is the right fish. They lose their color when I turn on the light. Very hard to photograph.

First picture close up, second comparison to normal fish.

Dark morph adult.

Brats are what I call the fish in the first three images. Dorsal spot very evident as well as other features I mentioned above.


Adult show the dark spot in the anal fin as well. Any Green Sunfish adult is capable of getting dark like that. Same goes for brat look which is adopted by Bluegill as well.

So you are saying they adopt those colors when they are annoying?

They adopt the coloration and the behavior that goes with it to defend something that is defensible, like predictable patches of food or cover. So colored fish show they are ramped up and ready to fight. The "brats" attack other fish entering their areas either driving them off or distract the others enough so they can not eat as effectively. In my larger tanks, a brat can almost exclude other sunfish from an area that can approach a square yard in size. My largest Hand-paint Bluegill (a female) outright attacks the other Bluegill that approach area under light where she gets first dibs on flying insects that either fall into water or come down close enough her to jump up for it. She only backs off, and just a little, when she is satiated. When we run feeding trials, each tank will have a couple brats that attempt to drive tank-mates off as fish are hand-fed. Our protocol with hand-feeding insures that all get most of what they want. What can be a problem is when we under feed or use an automatic feeder that meters out feed too slow. The brat can exclude other fish from eating setting up for size differential pretty quick.

You can see all this in ponds as well. Green Sunfish juveniles will defend areas near a nesting colony where they sneak in to eat nest bound broods. Bluegill will defend patches of bottom where they can pick of items like blood worms an tubificid worms they treat almost like gardens. I have seen Bluegill defend cover patches like a clump of plants where fish is apparently able to watch more diligently for zooplankton floating by. Sneaker males sometimes will also adopt the brat approach coloration.

Being a brat may have cost going with it. That would be why not all do it. Other sunfish species do it although much of color pattern change differs. Juvenile Smallmouth Bass and Spotted Bass do it to an extreme and the tri-colored tail is key to the display.

Your dark fish also look like F1 hybrids between (Green Sunfish and Bluegill). Pures of both do as I described and hybrids might be really prone to it.

Do you have a Zebra Danio in with those guys?

Yes, that is why I have already purchased a tank separator so at the first signs of hostilities to other fish I can separate the SF fry from the various tropical fish. If you would like I'd be glad to elaborate on what I've stuffed into the tank.

As far as them being F1 hybrids, I would call it good news because it would be the first signs that the BG, not just the GSF have spawned. They are trapped so we will find out if you are right in the coming months. It'll be interesting to see if the growth rates are different and if the HBG will pass up the 3 GSF fry that currently are the biggest.

I have a sediment pond that leads into my main pond. I stocked it with RES and CNBG. A few GSF somehow got in. I have lots and lots of hybrids produced from this small 1/10 acre pond.

I fish it heavily a few times a year to remove many of the larger fish. The GSF get tossed or tail fin clipped for bass food in the main pond, and the hybrids, CNBG and RES get transferred to the main pond.

We have been eating quit a few of the hybrids from the main pond in the 8-9" size range that originally came from this sediment pond stock.

I really like the hybrids. Grow fast, bite a hook easily, and fight hard. Some I believe to be CNBG/GSF and some RES/GSF. Once in a great while I see what I think might be a CNBG/RES but rare and not really sure about it.

The GSF characteristics are much easier to spot.

It's been a while and I'd like to update. Largest has grown to at least 3 inches. Quite a few are displaying adult colors and aggression towards each other. A few stragglers are still under 2 inches. Planning on separating the tank this weekend and moving them up to bigger food. The tropical fish have taken a hit from the GSF but not as expected. They ended up starving out the smaller less aggressive fish. They never attacked them, just ate all the food. No big deal. Anyone know how I can sex them? Would like to know if I have any females.

Squeeze them gently to strip for gametes.

There are several good threads on coloration and its many aspects. Jim notes the ones seen most in confined quarters (aquariums, small tanks or crowded conditions).

How important is it to know sex? Do you intend to tank spawn them?

It is not that important that I sex them. I mainly want to use the information to see the sex distribution of yoy in my pond by using this small sample. Also I want to see the growth difference and temperament difference.

You need to get a good percentage of the Green Sunfish fry to get a reasonable estimate of sex ratio. Minimum I have to be using is 30 to 40% unless the population is very large. Size at time of collection is important; make certain you get good representation of all sizes classes.

Something really screwy goes on with sex ratios within a brood (full-sibling) as ratio can be very much off from 50:50, very much. This is with pure, not hybrids.

I don't know if these are pure bred offspring or hybrid offspring because these seem like normal GSF but the largest fish in the pond are hybrids.

At least one of the early studies on sex ratios on BG X GSF crosses is/has been questioned due to possible GSF component genetics. It is possible that the 66% male figure was off due to the GSF genetics not being pure. So a little off can make a big difference in results.

Even pures can be off within a brood. If number of broods small, then it is very easy to come away away with conclusion sex ratio is skewed. Lack of proper replication plagues much of the data I see looking at sex ratios in sunfish.

Ok so I should not expect to be able to calculate the gender ratio. Is it ok to assume that the smaller less aggressive fish are female? Or should this be decided based on color, or physical features?

Final update on the project. Released the fish today. Pond water temp was about 65 degrees. 11 fish were released with the largest at 6 inches.
Conclusion from experiment is that GSF do not do well enough together to keep groups in a tank. The largest was separated for protection and it did the best. This might work if fish were separated into groups of 1 or 2 but I lacked that many tanks. I would like to try this with 1 or 2 LMB fry but not sunfish again.

Thanks for the report. Many sunfish are aggressive especially in confined spaces.

Yes they are. Just go swimming without a tee shirt around spawning beds and find out the hard way.