Zebra Danio died =S

[it4lian]

Well my male zebra danio died today (well he's barely alive, just barely moving his mouth and he can't swim, so he'll probaly die soon.) I had it in my 12 gallon with 3 more zebra danios (females) and a male crowntail betta. Before now I never had any problems, but I found him today on the bottom with half his back fin gone and he was bloody on the sides. I suspect my betta, because he's been kinda aggressive with that particular danio, never the females though. Should I worry about the females? THe betta doesn't mind them, but he'd always go out of his way to take a lunge at the male danio. Also is there a way to euthanize them (If he's not already dead, haven't checked in an hour), I'd rather it not suffer too much, cause it can't move and just is sitting on the bottom of a fishbowl that I filled with water from the aquarium. Or do you think I could somehow save it? (Doubt it) Anyways all help is appreciated. Thanks!

[trashion]

Guide to fish euthanasia here:
http://www.wisegeek.com/what-is-the-...ize-a-fish.htm

[oliesminis]

keep checking regulary as a dead fish can quickly pollute a tank

however i have a betta with zebra danios and they are fine together, is it a longfin one? as that may be a problem. it will also depend a lot on the betta as well i suppose.

however you do need to get a few more danios as if they are in smaller groups they can become nippy and have a go at your bettas fins

-olie

[Obsidian]

In a 12 gallon tank the betta can really only harass a danio "just so much" because danios are way faster than the betta. At most the Betta can, like you said, make a swipe on occasion. That is not enough to cause the damage you are seeing.

However if the danio was sick and slow the betta could have exacerbated this problem by attacking him more easily. In that instance then the damage could have happened over night while the betta had a better chance to get at him. Additionally his other danio friends may have had a go at his fins as well. It is very common for healthy fish to attack sick fish.

I have 5 danios in my 10 gallon and they do really well. I would say to get your group up to at least 5. You may have room for 7 but I think that is probably pushing it.

There may not have been anything to precipitate the loss of the danio, sometimes fish just die for general reasons such as stroke, heart attacks etc. It happens to everything eventually.

[it4lian]

Yeah, I was planning on getting 3 more for a total of 7 next week, but now I'll just get 3 more to have 6, also that danio was really slow and sluggish, unlike the other three. I couldn't see any outward signs other than him being slow, but i'm pretty sure it happened like you said obsidian. Also their not long finned ones(well at least I don't think they are). Yeh he died over night though, so ain't gotta worry about euthanizing him anymore. Thanks for the help ya'll.

[oliesminis]

he probably had some sort of internal disease/parasite which was slowing him down and making him weak, hope the others are ok.