I have a male koi betta who is extremely aggressive. He’s in his own 29 gallon tank right now (that I desperately need to make use of because I have overcrowding in some of my other tanks!). I’ve tried him with guppies, he killed one within about 30 seconds, so had to quickly remove the others, then some time later I tried again with lemon tetras, but same thing, he went on a killing spree and got two of them before I was able to get them out. I can’t even keep any snails in there because he picks at their antenna and will constantly shove them off the glass. I’ve tried keeping him in other tanks with dividers or in a breeder box, but he just thrashes against the side and will not settle down. Is there ANYTHING that I can keep him with or should I just give up and let him have his own tank? I don’t want him to kill anymore fish. I’ve had other males who I’ve been able to keep in community tanks without problem, so not sure what’s going on with this one!