D. imitator is a small arboreal frog that is very active and a pleasure to have. They lay white eggs, have a nice chirping call, and are very hardy. You need to make sure you have a well planted tank and plenty of food for them, but they are great. They like to lay in dark humid regions-- this can be accomplished by overlapping leaves. They also like new (smooth) leaves more than older ones. Many people like to give them much smaller tanks than they should be in. I found them very prolific and a pleasure to have.
They will do fine in colonies and in pairs. I started with four juveniles in that 50 gallon and pulled hundreds of eggs out of it, and even then when I cleaned it out after a few years there were something like 20 adults and probably a half dozen tadpoles in it. In the 90 I put a pair that were pretty just for fun. They started breeding the same week I put them in (after they were in a vert. 10-- and not breeding at all). That is why I stress them doing better in larger tanks. I like to have a lot of male competition going on with them, but really any numbers will do well. They were my favorite group to work with.
I keep a pair of imitator in a 20 gallon vert. The use the whole tank and are very active. I have tried 2.1 groups before, but one male would never keep on weight, but was fine when I pulled him. I never saw any fighting, but the males didn't like each other.
I would pull eggs twice a week and still had a lot. I no longer keep frogs as a hobby (just those for research in the lab), so sorry I can't help you out. Ben, that's interesting you had problems with the males-- it certainly makes sense, but I had never experienced it.
I tried that the 2.1 ratio as well in a 20H vert, and the larger male would bully the smaller guy. The smaller male held weight good but the bullying was getting very physical so I decided to split them up.
I have had a 1.1 in a 10 vert, a 10 regular, a 20 vert, and now a 15 vert. I have had them breed in every viv they have been in. I do like the bigger vivs because, I think, they seem more active and happy in one.
I have my established pair in a 15 now and wanted to try a 1.2 so I added an extra female. The females fought for about 8 hours one day and I couldn't take it anymore so I split them up.Now, I have 5 in a 20 vert but I haven't noticed any agression between any of them.Two of them look to be males so when one starts calling I think all hell wil break loose.Time will tell I suppose.