Tetra Tank

[ConorM]

I'm going to start a 20 gallon tetra tank with about 21 fish. First of all, is this too much? 20 will be tetras and 1 male betta. Will the betta be happy in the long run? Once I kept 5 phantom tetras with a betta in a 10 gallon, and they seemed OK, but they all died of velvet within a week, because I did a water change too early and it stressed them out. Has anyone here done this?

[Micho]

First off what kind of Tetras, some Tetras are not compatible with Bettas, some are.

[ConorM]

Ember, lemon, diamond tetras.

[Bombalurina]

Embers are tiny and have a tiny bioload (plus they are incredibly cute and get along fantastically with bettas, in my experience), so if they are part of your 20 I can't see a problem. :)
My only worry would be that that many small, fast-moving fish would stress out the betta. Again, not a worry with the embers since they are about as active as your average betta, if not even less so, but I'm not sure about the other two. :)

[BettaMiah]

No, please. Tetras are very fast and active fish. I think they would like a little more room. How about 10? That should be good. I always say 15 gallons for a school of 6 Tetras. So you could do ten if you really wanted. But please, do not get 20! That is a little crazy. Even if you follow the stupid 1" per 1 gallon rule!

[Micho]

Lets see, Ember Tetras seem to be tiny little fellows, fare better in a shoal of 6 and higher, only grow up to 0.8". The only thing I'm scared about is that if your Betta can fit one in his mouth he might, but they're probably way faster than him so no worries.

Lemon Tetras, same deal 6+, they grow a tad bigger though 1.6", really compatible like Embers, I see no problem.

Diamond Tetras, now these guys get quite big 2.4", plus they might fin nip your Betta's fins. But if kept in a small shoal 6-8 they'll keep the fin nipping inside their little group, but be careful.

Now I calculated with AQadvisor, if you have six of each fish, which is the minimum of a shoal you'll get a 66% stocking level, add in a Betta it goes up to 70%, so I'll say that you're doing just fine if you add in your Betta. Just watch to see if those Diamonds will nip him.

Either way, if it's heavily planted has a good filter, I really see no problems with adding your Betta in other than him getting stressed because there's too many shoals of fish, or that the diamonds are nipping him.

:] Good luck and keep us updated.

[Pitluvs]

Twenty 0.8" fish and a Betta in a 20g tank is a little iffy to me. Thats a lot of verticle space, but not a lot of horizontal space for territory and swimming. It's not just water per fish, but horizontal room per fish. I have 5 Glowlights (2" max), 6 Celestial Pearl Danios (0.5-0.8" max) and a Dwarf Gourami (2" max) in my 15g. The reason why mine works is because my fish live on different levels of the tank (CPD bottom, Glowlight mid, Gourami top). If they were all mid dwellers, I'd be in a lot of trouble.

[Bombalurina]

Personally I'd go for two schools rather than three, and do maybe 8 of each. I think the embers and the lemons would be nice. Alternatively, embers look great against neons or cardinals.

[dramaqueen]

I'd go with 6 Embers, 6 Lemons and 1 betta.