Could you keep fish in a container like this?

Depends. I've used something similar for some live breeders for a while, and they work well with pond plants. The problem I had was keeping it well lit inside, and at a stable temp outside.
 
Yeah I noticed the water in there can stratify and I do get algae problems.
 
Gambusia said:
I have something exactly like this to keep some water plants in:

http://www.maccourt.com/products/ponds/pp3814.html

I've kept mosquitofish (gambusia) in it.

Could you keep anything else?

Thanks
Gambusia,
If I had the room and space outside these would be great containers for keeping fish for breeding during the summer.
I use outdoor containers for Live bearers all the time. And I have a whiskey barrel that I use very often.
Plants I use often are
Hornwort
Various Lilies
Water Lettuce
Water Hyacinth
I like to stay away from duck weed since it likes to take over.
I think a system like this would great for breeding Rams outdoors or any other small fish you would like to breed.
Fish color becomes more vibrant when kept outside and the health of the fish are far superior as well.

Check out the article by Dr. Ted Colletti
http://tcoletti.tripod.com/take_it_outside.html
And also check out this article in FAMA.
 
Gambusia said:
Yeah I noticed the water in there can stratify and I do get algae problems.
That is why you can use floating plants to help block and give the water shade. I wouldnt knock these style of setups, they work very well, as long as you keep them in a slightly shaded area, or buried to help cool them off and give the temp a more stable setup.
But most of these are for water plants and a fountain but not expected for large fish.

also since the sides are black, you really can not see the alage on the sides.
 
What kind of fish were you thinking of? You could easily keep some of the smaller species in there either inside or outside. Personally I have a 180g pond outside that is made of the same materials (one of those hard plastic formed ponds) and I keep comets goldfish, tadpols, fancy goldfish, (tried Koi once) and even black skirt tetras.
 
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