I have a long fin danio that is really mean does anybody have I idea what I can do whit him I would hate to kill him or give him away pleas help I'm desperate
Danios, like a lot of shoaling fish, are notorious for being aggressive if not kept in a large enough group (6+).
If you can't get another five to keep him busy and out of trouble, it really would be best to rehome him to someone whose got others for him to mix with.
he is a schooling fish, numbers should in around 6+
separate him or sell him, or trade him for a fish at the pet store.
unless the fish is on its way out.. unable to swim properly.. nose diving, skinny, not eating that IMO is the only time to kill a fish. pulling it out of its misery.
If you cannot or refuse to re-home the danio, you could get a bigger tank and do a fishless cycle and then get at least 5 more danios and put your single danio with them in bigger tank.
Which species of long fin danio? there are several species, one being Zebra Long Fin Danio.....they are basically the same as Zebra Danios but bred with long fins, can be gold or silvered as well.