Pond Boss Forums INTRO Questions & Observations Warmouth questions

At what size can warmouth make nests. Can a 2" male really guard a nest?

Interesting question. My completely knowledge-free guess is "No".

The fish looks like a sunfish in shape and is only 2" long. I only put warmouth and FHM in the pond and there is no "natural" way for fish to get in. The fish in question would have to be the offspring of the warmouth that I added or they did not grow since they were added 2 years ago. I only stocked 10 fish.

If there are zero LMB or GSF, then I would think a 2" warmouth can guard the nest against other 2" warmouth.

However, he probably can't effectively guard the nest against a 6" warmouth. Hopefully, you have reduced that problem in your pond because the larger warmouth will be guarding their own nests at the same time.


P.S. I still believe YOU are going to become our foremost warmouth expert on the forum.

Do you have any need for a drone to patrol your property? Learninboutfish has done some amazing sampling of the fish distributions in his pond using a drone when the water is clear. He has a fairly pricey drone, but he told me in a PM that even the inexpensive entry-level drones are now easy to operate and can take decent video.

That could even help you during deer season to monitor your property for deer movements or spot poachers?

No drones in my near term future, but maybe when I get old,😃

As a followup, I went out the next day and the warmouth was barely 2" long and still guarding the nest. The following day, I did not see him.

Very small sunfish in a near empty pond will try to reproduce as soon as possible (a survival of the species adaptation). BG can reproduce quickly at 3-4 inches (4 to 6 mths old) under those circumstances. Not sure at all about WM at 2 inches however.

It was a real surprise to me and "the internet" says 3" is the smallest size. That is one reason I went back to see if my 2" estimate was accurate. It was 2" at the biggest, and kinda skinny like small sunfish often are at that size - not beefy or fat.

I think both things can be true. An internet statement that "2 inch warmouth are too small to spawn" is true as the generalization of information it is meant to convey.

However, there can possibly be a 2" male that is in the 95th or 99th percentile and is trying to spawn. Who knows, his year class may be 4-inchers and he is a runt?

I certainly would award him an "A" for effort!

The Mickey Rooney of warmouths.

You have more faith than I do regarding some sources of information. Purdue's pond fish recommendations still claim that smallmouth do not do well in ponds even though I actually contacted them back during COVID to suggest they had old info. The PhD I spoke to said I must have special water conditions even though I explained smb do fine if there are no lmb or bg. Some folks seem to think they know more than they do and stop learning. Experts on this site are the only reason I have had a great smb pond for years.

RAH, I do think those smaller WM are offspring of the originals. WM grow slower than BG and RES ... comparable to GSF. Once they attain around 4", males can grow up to about .16 lbs annually in your climate. ~6" inches at 1.5 years is or is near the upper limit. Males do grow faster than females. With only an initial stocking of 10, those initial probably grew at their full potential the first year. If they grew at near maximum rates of growth ... and were stocked at 2" ... there could be some males around 7.5" in length presently.

With regard to the minimum length or age to spawn. I recall a Texas study where the research found that the length (of an altogether different species) depended in part on age. Shorter fish became mature at greater ages and vice-versa. But the pond has been stocked only for a couple of years and it seems likely that the fish that you referred to is either from last year's or the initial year's YOY crops. I lean towards last year's crop but if the they reproduced significantly in the initial year ... it is possible that the fish is approaching 2 years.

Thought I would mention a couple of things about balance. Without any predators other than the WM themselves, they probably have reproduced more abundantly than could support moderate/fast growth. Wanted to ask how the FHM are now doing. If they have been extirpated, good chance growth is now going to be slow going forward. The smaller WM being survivors of predation by their WM parents have probably reached a length that can only be consumed with difficulty or not at all. Bill Cody introduced a practice to the forum of adding a single LMB to a small pond to provide predation to a less fecund species. Being a 1/4 acre pond, it may be a good candidate and you probably could spare one from your LMB pond if you chose to do it. FWIW, I would want the LMB to be 4 to 6 times the length of that strong year class of forage. At 2.5" Forage ... I would want an LMB of 10" minimum length. Though it may not provide sufficient predation for the WM grow at full potential ... i would think it would have a positive influence on growth and condition of the WM.

An additional option for selective predation on the WM would be to add just one cannel catfish. When larger than 16" the CC have a larger percentage of fish in their diet. CC would be eating WM during low light periods and a LMB will be eating WM during the day. Two good predators and no reproduction problems in 1/4 acre.

A 3rd additional item as a predator in your pond with WM would be to move just one smallmouth from your main pond into the WM pond. Smallies will not eat as big of a WM nor maybe as many WM as a LMB but you still have very good control of the amount of predation that occurs in the pond with WM. A local pond owner near me has one SMB and one LMB in his 1/2 ac pond with GSF and yellow perch and each of the bass are growing one pound or more per year with good control of the panfish.

RAH - I am being nosey. Why are you interested in growing WM in a small pond?? Literature does say they can in the right conditions grow to 10" to 11" long. They probably could be trained to eat pellets. Larger individuals like woody shallow water and vegetated habitats.

Thank you for your interest. This is my leaky pond with an attached wetland. It has a deeper trench down the middle of the pond section and lots of "weeds" growing in the shallows. As a fourth pond, I just wanted something different. If I had access to pumpkinseed or chain pickerel, I would have gone that route and might find some grass pickerel at some point to add. I also considered trying walley since I have a shallow section connecting the pond and wetland that seems to get a lot of wind that might keep rocks clean some years. I retired about a year and a half ago and have been busy playing on our property. In addition to the habitat work, I am building a shop area in our large pole barn. Just puttering and having fun. I always value you input!

My uneducated WAG is that was a GSF that you saw. I saw 2" GSF on nests in a pond that didn't have any predators in it.

No gsf in pond, and I could see it well enough to say with high certainty that is was not a gsf. No entry point even in a huge flood.

I can't remember the forage base for your warmouth pond.

Do they still have ample food? I could see them being efficient enough predators that they have extirpated your initial stocking of FHM.

Lots of fhm but tons of tadpoles and insects too. Guessing the insects and other invertebrates are the main food for the small ones.

Younger FHM too.

Only way to tell for sure is to catch it and take a picture!!

I only added 10 stockers so I am not going to risk injury or death until I am sure they are at a good population.

While pulling cattails around my "warmouth pond" yesterday, I saw quite a few small warmouth in the shallows. Surprised to see them in the hot water but glad they established. Lots of tiny fhm as well. Will probably need a predator for them in a few years that will hopefully tolerate the low o2 that I expect is occuring in this pond, although the water is very clear a lot of the time. Also full of plants due to a lot of shallow water.

Thank you for reporting your observations. It's great that they are thriving in the conditions of this pond that you have described. FWIW, the choice of WM in this shallow vegetated pond is a really good match, IMHO.

If the fish you are seeing in the shallows are between 3"-4", these are probably from last years crop. Not seeing large numbers of them is probably better than seeing large numbers. If the growth of last years crop was near maximum (3"-4") then probably your initial stockers did too. WM, do begin spawning a little later than BG. Around 70F. I earlier put together a climate model for your county when you first reported stocking WM. That model puts the initial spawn each year at the 15th of June. Given the vegetation and shallow depth, your pond may warm to that temperature sooner ... IDK. But June is spawning season for WM in your neck of the woods. In addition to your FHM hatchings, you might also observe WM YOY, which if they got off good spawn, could be abundant now. Their lengths will depend on their swim up date and the supply of food. There is a good chance they grew at maximum rates of growth due to predation by their parents. Using Saturdays as swim up references, the lengths at maximum rates of growth would be as follows:


Swim up dates:

6-4-26________ 13mm
6-11-26_______ 11mm
6-18-26_______ 9 mm

So any WM surviving from these swim up dates would range between 1/3" to a little over 1/2" in length. Not knowing the difference between the appearance of small FHM and small WM when viewed from above, I can't tell you what to look for to distinguish these two inhabitants. But a few small samples taken with a long handled small mesh net may give you an idea of those populations of small fish.

WM grow slow enough at maximum rates of growth to be vulnerable to predation by their parents for much longer than smaller mouthed species like BG. The fecundity per unit weight of females is reported to be very comparable to BG. Still there isn't as much known about WM, for example, contributions to year class from additional spawning after the initial wave. But the slower growth and large gape of the species seem to help it from overpopulating as much as BG and other species of sunfish. This may explain why some report that the species has not been observed to stunt as frequently as other species. Anyways, I am very interested in the progress of your pond ... even given the challenging conditions you describe. Hopefully, the pond will seal better with time providing better conditions. Looking forward to your future updates.