Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Grass Carp vs Tilapia

Ok, so after about a year here on the forums, I just had someone ask me for advice on thier pond. What the hell was he thinking, I dunno.

So he has a big weed and algae problem in a ~4 acre pond in central MO with an average depth of 8ft across the majority of the pond. I've not seen it to tell you what kind of weeds it is, but the issue is what fish to stock to help control the aquatic vegetation. I suggested looking into chemical treatment, but all involved seemed to shy away from that idea.

I don't know the company they used to stock fish but apparently they gave 2 recomendations, grass carp or tilapia (tilapia are verocious weed eaters, aren't they?). The stocking company said carp was the way to go, since tilapia could take over the pond and would eat the eggs of other fish species.

Does this sound accurate to anyone? You all know i know very little to none of what i am talking about, but for some reason i had gotten the idea that tilapia would die off after a little while, since they are native to a more tropical climate than MO. So what's the deal? Anyone want to set me straight on this once and for all?

edit: already stocked are BG, LMB, Some large catfish and BC
pond was built by my friend's grandfather, roughly 40 years ago

Hey Skinny,

You are correct in that tilapia will start to die off around the 50 to 55 degree mark from what I have read. The pure blue strain can last to as low as 45 degrees I believe but don't quote me on that. Rainman is the expert in that department but I think I am close to the numbers. So that means you would have to stock them year after year and that could get pretty expensive in a 4 acre pond. Of course depending what type of weeds they are the Grass Carp will take care of them but he won't see much the first year or so. He will need to be patient. I stocked 7 in my 1 acre pond last year and my pond weed is almost all gone this summer except for about 10 percent of it. I still have a Chara problem and I may not have enough GC to do the job on that stuff as it spreads FAST!!! And they may not be able to keep up this year. At any rate I have had pretty good success the the GC when it comes to weeds of a certian type. You may want to find out what type of weeds he has first. I am no expert but I believe Tilapia are more of a algea and organic eater (Bottom Feeder) than weeds. I have been told everything from 5 GC per acre to 12 per acre. I went with 7 and I seem to be doing pretty good. With all the Chara I have I may need a couple more but the jury is still out on that. Anyway hope this helps. If it were me and he wants a natural way of getting rid of his weeds and something he can put in his pond and not have to restock every year than I would go with the GC. They say once you put them in there you don't really need to replace them for about 5 to 7 years. I guess at that point they start to not do there job very well anymore and you need to restock some new ones. The only problem is getting rid of the old ones??? That could be a little difficult. Like I said I am no expert just giving you my advise based on my expeirence thus far. Oh and one other thing you need to make sure the person can actually have GC in MO?? I believe in some states your not allowed to stock them.

Good Luck with your pond mentoring bud...

Skinny, I have a few thoughts and trust the experts will chime in.

Blue tilapia will die off when water temps hit around 45 degrees, so no danger of them overpopulating. Other tilapia species die off at higher temps.

Tilapia will eat about any vegetation, while grass carp will turn up their noses at a number of plants, including FA and some plants that have grown beyond a certain point of maturity (my reading posts here and info on the web suggests that as certain plants develop some characteristics make them less desirable than newly emergent plants).

Grass carp do their thing well for a fairly long period of time before becoming lazy and pretty much nonproductive. Tilapia will have to be replaced annually, but a heavy stocking for a couple of years may well help get certain vegetation under control, allowing lower stocking rates later.

I doubt that a pond already stocked with predators will suffer much predation of eggs/fry of your primary species as the tilapia adults will be busy eating vegetation and their fry will be busy getting eaten by YOY predator species.

I think a lot of it will depend on what plants are in the pond so before you can give a really useful answer, you'll need to know that info.

Let's see what the others have to say.

Hey thanks, guys.

It looks like they took the salesman's advice and went with the carp. Apparently they have done it before and experienced good results, so they went with what they knew. Meh...At least i am informed now

Also, i checked online using an acreage calculator, and it is 12.92 acres. not 4, lol.

See? I can't start a thread without showing how uneducated a question can be.

For now they got ~30 GC, and will do the same next spring when the hatchery has more to sell, i guess.

Thanks
Skinny

Hey skinny,

That will help out for sure. So from what it sounds they are going with about 5 per acre. Which is not a bad place to start like I said you can always add a few more if need be but taking them out won't be as easy. Sounds like they got a plan and you got off easy!! Just kidding. Have a good one.

Skinny, I would privately like to know who the stocking company was for 3 reasons...first to educate them, second to inform them tilapia are illegal to stock in Missouri, and third is really more education because they are seriously misinformed on tilapia taking over the pond in Mo. or eating eggs....

check your pm's rainman.

Tilapia may have come up as a topic after I hinted that i thought they ate lots of vegetation. see? uneducated as it gets. But at least i admit it.

The legality issue was not among the reasons why GC were suggested.

and yeah, looks like i got off easy! haha...this is the kind of advice giving i like...even if i was wrong, it's not like it really matters. the pressure is off!

Thanks for all the help, everybody.

-Skinny

Sometimes salesmanship 101 says good things about what I am selling, disparage stuff I don't. I have heard Tilipia are the Devil's spawn and have been known to eat humans like pirana.

Stocking less than 3 GC per acre is like using a flashlight midafternoon outside. And before I even thought about them it would be nice to know what you hope they eat.

Too many times on this forum I have seen people getting sold by guys more interested in making a buck then helping out. Or it's just coincedence they happen to sell what the happen to suggest.

I think the less than 3 per acre is just temporary, as soon as next year rolls around i bet they get a few more.

Thanks
Skinny

There is some outfit north of KC selling tilapia for pond stocking.http://www.tilapiasource.com/

They ran into a salesman alright.

"Hey, we don't see any difference in our aquatic weed problem."

You need a few more, buy another 30.

Repeat forever.

I have seen threads here where guys just did not have adequate stockiong rates, and thier weeds got worse. Speaking of, what are the weeds anyway? We don;t even know that, might not even be on GC menu. So these guys had to keep bumping their rates. Up to 10 an acre. Still no good. Up to 20 an acre, have not heard results yet. This is not GC vs. Tilipia. This is getting sold.

That would be Kellen Weissenbach and his wife Sarah. Good people and forum supporters! They sell a high quality Nilotica (Nile) tilapia.

How do you sell a fish that is illegal to stock in your state? Out of state only?

We keep them in closed systems and use a liability release to sell to restricted states...The customers must abide by their state laws. California is the only state to confiscate an order...the CaF&G officer told the customer she couod get the fish then confiscated them.. Ca recently made possesion of tilapia illegal in the northern part of the state....Except for Ca and Northern Florida, tilapia can be kept in closed systems without restriction, like any other aquarium Cichlid.

CA informed me Tilipia were the Devil's spawn, and not to possess them or they might possess me. Last thing I would want is an exorcism for Tilipia possession. I still have this fear the Reverend would just show up and punch me in the nose.

CA F and G: Sure you can lady, you can order them. Oops, they are illegal to possess, thanks for the fish lady.

God blessed the truly uninformed in California!!! My favorite is the Salton Sea. Absolutely destroyed by idiotic regulations, yet a thriving fish population has been re-established for one single reason....tilapia convert unusable nutrients into forage for other fish....go figure..

Perhaps Ca should change the name of Salton to the devil's Advocate....hehehe

If it weren't for tilapia, the Salton Sea would just be another dead sea.

Sorry I know this has probably been asked many times before, but do some people use the grass carp and the tilapia to control aquatic vegetation?

Hi Zep, i see that this is your first post. Someone much more informed than I is sure to come along in a moment, but I'd like to welcome you to the PB forums.

And yes, i believe this to be the reason most people use GCarp and Tilapia (although i hear tilapia are awesome for table fare and make for great angling).

Thanks
SB

Hi Zep, research both fish well. White amur (grass carp) and tilapia's are not legal in many areas. GC do not touch many things tilapia will eat, but tilapia die in 95% of the US annually during the winter. Each has a good place in your pond management needs.

Welcome to the forum!

Thanks guys. This looks like a great site. Sounds like it might not hurt to have some of both....tilapia and grass carp. I am contacting a local expert suggested by Rainman. Look forward to learning a lot on PondBoss.

I think my blue tilapia in a cage are eating bushy pond weed (northern water nymph, slender naiad, Najas flexilis). More information on this later after more "testing".

Rainman what is the reasoning behind Blue Tilapia not being allowed by law in Texas? From a legal standpoint what is the argument that Mozambique Tilapia are allowed in Texas but not the Blue Tilapia? Are they worried that in a mild Texas winter and Texas being so large as far as differing temps that the Blues could somehow survive and over-populate?

Zep,I would assume it is the better cold tolerance of a Blue that is the main concern. pure strain Blue Tilapia are proven to survive to 45* water temps where,IIRC, Pure Mozambique will kick it at 58*.

Either species becomes lethargic plus start to succomb to infection, disease (from a depressing immune system) and heavy predation 10-15 degrees cooler.

Any recent information on how to naturally control weeds?

I have ceratophyllum (coontail/hornweed) I’m trying to control—- GC & blue tilapia is what I think is best recommendation? I live in NE Texas.

Only Mozambique tilapia in TX, and they will not eat coontail.

Grass carp do eat coontail, but be diligent and do your research before stocking them. Too many can create turbidity problems once their food source is gone.

Thanks much. When referring to turbidity problems,.... can you explain?

Sure. I think I read on another post that you had a 3 acre pond that was infested with coontail. It's been a while since I first got my GC, but TPWD will issue a permit for a max of 10 per acre if the total coverage is over 50-60%. That permit is good for 10 years, and no more can be added until the permit expires. "If" you initially stock all 30, and they don't control the coontail, you'll still have to chemically treat the coontail. If they do eliminate all the coontail, then they're going to be rooting around looking a new food source, and will muddy the water. I've got 110 in my pond, and and I ladder stocked them over the last 8 years.

I've resolved myself to having to deal with a limited about of coontail, and the GC are now handling most of it. I still treat with chemicals, but at not near the volume that I used too.

Grass Carp Permit Info - It can take weeks to months to get the permit, so I would handle that first. TPWD may make you go exactly by the fencing info if a public BOW is downstream of you. My pond is at the top of Lake Fork, and it took me months to get the permit. Others with no downstream issues get the permit quickly.

Aquaplant Coontail Control - A great source of information on pond plants, and their control.

Thanks for the great info, Al. Looks like I'm gonna need it.