Ahh ok. Be warned, the gouramis are actually the cousins of bettas - and may not get along so well with him :) they (and the pleco) also have a huge bioload! Which can cause lots of ammonia, causing sick or dead fish... Which we don't want you to have to deal with.
As for the behaviour, the 10 gallon isn't enough space for everyone, which is why you are seeing odd behaviour. If both gouramis are males they scout out territory... And will attack, and kill, anything in their chosen domain. As will the Betta. Personally, I'd say to get a bigger tank ASAP, and leave the betta in the 10 (you can find different tank mates for him later), and have the gourami and pleco in the larger tank. The kissing fish... He too is a gourami.
link to care for the kissing gourami.
For the gouramis (I want to gues you have dwarf gouramis, which depending on the strain may get bigger or stay smaller)
Pleco not sure which one you have, pictures would help :3
Just to help you out :) you've got some interesting fish - we want to make sure you have the best experience that you can have, owning fish.
Breed for the breed, not for the money; the words any REAL breeder would understand.
You must know nothing in order to know all, for all is nothing and nothing is for all.
Last edited by Oldfishlady; 02-07-2013 at 06:05 PM.
Reason: links removed to another fish forum