All right, so after getting a 30-gallon Oceanic Cube for a real bargain (free) it's for sure that I'll be putting each of my four in their own 10-gallon space; Ezra and Kostya will get the 10-gallons that I have, and Bebette and Haifisch will get the cube divided and filled to 20-gallons (this gives them about the same dimensions as a regular 10-gallon if I did the math correctly). All of these will be NPTs.
I would really like to get them tankmates -- none of them seem too aggressive for that, and they seem to like watching each other so I figured (correctly, I hope) that they might enjoy other living things in their tanks with them.
Ezra I would like to try with some Ghost Shrimp (10-12, I think) and a couple of African Dwarf Frogs. The other three I'm still working out...I think maybe some Red Cherry Shrimp with Kostya (if shrimp work out for the both of them). I doubt shrimp will work with Bebette as she likes to bite things, and I'm not sure how Haifisch might take to them.
I do want to keep Kostya with gravel because he likes to hunt the crevices, but otherwise I'm willing to do sand.
Now, for the fish I'm considering (it might actually be toughest deciding for Kostya, and I may just do shrimp and ADFs with him too if that works). I've looked into all of these but I also wanted to see what the thoughts on them are here as sometimes I learn things here that are not readily available through a more general search.
As far as I know, what I have available to me are: Harlequin Rasboras, Mosquito Rasboras, Galaxy Rasboras/Celestial Pearl Danios, Kuhli Loaches, and a couple of Corydoras that might work.
It seems that the Harlequin and the Mosquito Rasboras might
work. Are these guys nippy at all? I'm more inclined to put them with the girls, honestly, but that's largely on the chance that they are nippy. From my understanding they need at least 6, correct? Or is there a better number? After toying with AqAdvisor I'm thinking 8 for the Harlequins and 10 for the Mosquitos.
The Galaxy Rasboras/Celestial Pearl Danios I'm not sure will work. I read at TFK that they are "shy and quiet by nature" and that they recommend them having their own tank, but when I've seen them they did not seem to do badly at all and were not stressed in community tanks (perhaps I was wrong?). Thoughts on these guys?
I'm also not sure on the Kuhli Loaches -- how large of a tank is recommended for them? TFK states "a minimum tank size of 20 inches for a group of 6" and that the minimum is 5 Kuhlis; I've also seen recommendations of 15-20-gallons for them. I know they do best with a sand or fine/smooth substrate, and that they should be treated as scaleless fish, but otherwise...thoughts?
Finally the Cories. I am able to get my hands on the Pygmies, but what about Pepper(ed) Cories? Would four of those in 10-gallons work? I'm partial (aesthetically) to the Peppers over the Pygmies, to be honest.
Yet again another wall of text from me, but it's probably as succinct as I'm going to get it. Thanks in advance for reading/helping.