barbs

[cornbread_5]

Torpedos do indeed like cooler temperature. You could try a panchax for a 30g as these are 4 inches. The only trouble is these are excellent jumpers. As for the 15g, I don't think any dithers will survive even if you try the convicts in there.

a 15 gal and 30 really is not that much of a difference a 30 is just taller

 

[cornbread_5]

Tiger barbs get pretty big, about 3 inches or so. They would be pretty good for the smaller tanks. Giant danios are generally a fish that is recommended to be kept with mid sized cichlids. They get about 4 inches long, and they are really active, so I wouldn't put them in anything smaller than the 55. I've got 5 in my 75, and they use the whole tank. They stay in the upper levels of the tank almost exclusively, which I think helps them avoid aggression from cichlids that lurk around lower to the bottom.

it would help to know what is in each tank already.

I tried giant danios and they was getting picked off one by one by my pike but i got rid of him so i might try them again

 

[FSM]

Picked off as in eaten? because pikes are more carnivorous than other cichlids.

 

[cornbread_5]

yes eaten