Raising fish in large stocktanks.

So I am not able to build ponds to breed fish outside, but I could squeeze in a few larger rubbermaid stocktanks. I could do several 100g gallon rubbermaids or two 300 gallon stocktanks. I have some smaller ones right now, but I maintain them like tanks indoors with water changes. Would it be possible to set up a 100 gallon stock tank to breed something like lepomis humilis, or would I need a larger tank. I'm hoping if I seed the tanks with as many plants and as much pond life as possible then the fry will grow quickly to a size where they're easily fed.

Is it a good idea to place a tank in the open exposed to full sunlight? I would add many plants for cover, but I would still worry about letting it get too warm.

Thanks a lot.

Partial sunlight would probably be best.

Would it be possible to set up a 100 gallon stock tank to breed something like lepomis humilis, or would I need a larger tank. I'm hoping if I seed the tanks with as many plants and as much pond life as possible then the fry will grow quickly to a size where they're easily fed.

Is it a good idea to place a tank in the open exposed to full sunlight? I would add many plants for cover, but I would still worry about letting it get too warm.

Paul Sachs of Sachs Aquaculture successfully raises a variety of sunfish in 100-300 gal stock tanks outdoors, as you are suggesting. I know he has humilis, and I'm pretty sure some of those are part of his outdoor set-up. In St Augustine, Florida, so it gets warm, and most of the tanks are not shaded. Some are probably 3' deep, so I assume they're cooler at the bottom. Plants may not be necessary for cover. ("And here is my stock tank of _____ _____." "Oh really? It looks like the world's largest private collection of guacamole. Are you SURE there are fish in there?")

Filtration and probably aeration are of course necessary considerations. If the water's 85 degrees or better, D.O. will be low without some help.

d.d.

I'm not surprised that Sachs can raise L. humilis in warm, funky-looking water. They're often found in turbid waters with low flow. But mid-80s F sounds like it would push the species' thermal tolerance.

Bigger is always better I think. The 300 gallon rubbermaid has an excellent footprint but it's the same height as the 150 stock tank so you could easily roll it through a standard door. I plan to grow out fry from several of my African cichlid species in 50 gallon stock tanks just because they have such a nice footprint without all of the height on a glass tank with similar volume. They aren't the prettiest in the world to look at, but they are cheap, large and lightweight.

So I am not able to build ponds to breed fish outside, but I could squeeze in a few larger rubbermaid stocktanks. I could do several 100g gallon rubbermaids or two 300 gallon stocktanks. I have some smaller ones right now, but I maintain them like tanks indoors with water changes. Would it be possible to set up a 100 gallon stock tank to breed something like lepomis humilis, or would I need a larger tank. I'm hoping if I seed the tanks with as many plants and as much pond life as possible then the fry will grow quickly to a size where they're easily fed.

Is it a good idea to place a tank in the open exposed to full sunlight? I would add many plants for cover, but I would still worry about letting it get too warm.
Thanks a lot.

I'm raising about 1000 bluegills in a 300 gallon circular stock tank with a homemade biofilter and clarifier. I thought I had a post here but couldn't find it. If you want to read about it it's here:

http://www.aquaponic...re-System/page4

I got directions on how to build the RBC and clarifier from the book Small Scale Aquaculture by Steven Van Gorder. Excellent book for under $25.00.

BTW as a former resident of Massachusetts I know exactly where you're at. I used to live at the former Ft. Devens as a kid when my dad was a Green Beret. I have a lot of fond fishing memories in Massachusetts.

Edited by az9, 18 April 2010 - 10:22 PM.

Maybe in Alabama, but in Oklahoma they are found in rivers that get pretty hot, probably at least 30-35oC if not hotter. Maybe there are some thermal refuges they seek out, but everything in western OK gets very very hot.

Cheers
Peter

I'm not surprised that Sachs can raise L. humilis in warm, funky-looking water. They're often found in turbid waters with low flow. But mid-80s F sounds like it would push the species' thermal tolerance.

Maybe in Alabama, but in Oklahoma they are found in rivers that get pretty hot, probably at least 30-35oC if not hotter. Maybe there are some thermal refuges they seek out, but everything in western OK gets very very hot.

Cheers
Peter

I concur AP. As a fish grower I've seen literature shows the fastest growth for lepomids in the 80's F. I would think as long as there is sufficient oxygen they should be O.K.

Sufficient oxygen is the rub, since warm water holds a lot less O2. That's what I meant by thermal tolerance; water with any dissolved material in it holds even less O2. All the metabolism of a fish will be cranked up by higher temperatures but available O2 is a serious limit. Peter mentioned thermal refugia, they would have to be available. If you follow the logic of warmer water you'd have monster o-spots in farm ponds or clearcut woodlands, and that ain't the case.

Yes, of course warmer water holds less D.O. but even at 30 C. water can hold 7.5 mg/l of D.O. at saturation. Of course that may not always be the case in natural conditions, however, I've actually seen levels over saturation where filamentous algae or phytoplankton is very active.

My ponds rise into the mid 80's in the summer and my bluegill are very active and healthy at those temps. I use a diffuser to mix the water column but don't use any vigorous surface aeration unless needed.

Edited by az9, 20 April 2010 - 10:11 PM.