I am learning, after trial and error, that one male Powder Blue per tank is enough. They fight otherwise, and the lesions that they cause, by injuring each other, do not heal well, and result in nasty looking sores. They are a very beautiful fish, but one at a time guarantees their well being. I now regard them in much the same way as a betta - one per tank. I keep mine with 4 of the small golden dwarf gouramis and a range of tetras, loaches and a betta. He interacts quite a bit with the Gold Dwarfs, but it is not as aggressive as what happens when I have more than one male Powder Blue in the tank. I haven't kept females, as I like a bright coloured tank - females are duller in colour.
I started out my aquarium with a pair of beautiful baby powder blue dwarf gouramis. I didn't know anything about these fish, but saw them in a store and was amazed by their beauty. They have been extremely peaceful and timid, and I have since added another baby powder blue male. Powder blue's are wonderful community fish and seem to enjoy other powder blue's company, but are very timid towards other fish. Beware when adding other territorial dwarf gouramis, as powder blue's will tend to starve themselves to avoid conflict!
I own 4 of these beauties. I have 2 males and 2 females. Strangely, they get along fine with three small cichlids. The only problem with these magnificent fish is that the males tend to fight. If you plan on getting some get only one, or all females (their fins are more rounded than males). Or if you plan to breed them have a few females to a single male. Once he has chosen his mate move them to the breeding tank. Make sure there are floating plants for the bubble nest. If you are a rookie at fish breeding maby you should start with another fish to breed.
For my first tank, I bought a pair of powder blue guaramis four months ago now. They look stunning in a tank with neon tetras, harlequin rasboras and a pair of red sunset dwarf guaramis. There was a bit of aggressive behaviour, circling and agitating their tails between any two gouramis in the early stages, but that has since died down as each now seems to have his own territory in the tank staked out. Since one built a bubble nest as soon as he was placed in the tank, I did buy some females for them, but they died after a few weeks. It seems that they are more herbivores than carnivores and I was feeding them worms - fresh and frozen, on a daily basis, thinking it would bring them into mating condition. I now make sure their diet is more vegetarian. They love mashed peas and small chunks of cooked zucchini, but their favourite is broccoli and they will nibble the florets of well-cooked broccoli from my hands. Females are hard to find and I haven't been able to replace them yet to try breeding. I have an old piece of cork from an unused lid and have used an elastic band to attach java moss to it. The gouramis have taken a lot of interest in this partially-made bubble nest. How they intertwine java fern roots around the moss with only their mouths is amazing. They really take some untangling before the fern can be replanted. Two bunches of Ambulia were also shredded in a few days by these plucky little fish. Now I have plastic Ambulia because I love that ferny appearance and the gouramis leave it alone. Weekly water changes keep the fish happy as my tank is well stocked for its size. These fish have given me a lot of pleasure and I'd recommend them to anyone prepared to keep their water quality as good as possible.
I added a Powder Blue and a Dwarf (both male) to my community tank (consisting of Cardinals, two Panda Corys and Danios) about a week ago. The Powder Blue acted completely aggressively from the first moment it was introduced. I monitored it for a day or two, but unfortunately that was too much time to avoid losing a Cory, two Cardinals and my Dwarf Gourami. The most curious fact was that it never went near my Danios. I then took it out and gave it back to the store it came from. I hope to one day try again introduce a Powder Blue to the aquarium because it is so beautiful. (This time Iíll try introducing a mating pair with -hopefully- better results.)
I just bought three of these fish for my 110 liter tank. They are quite active, colourful, and beautiful to watch. Although I do not know their sexes, they do not seem to be aggressive at all, at least, so far :-). They seem to enjoy and appreciate a planted tank.