That's what I was thinking. But I'll just wait to move some fish out that would be larger and possible culprits then look for another. Though I do have the 20L but I use it for a hospital tank.If you can keep them separate and can remotely afford them (that's where I usually stand with fish purchases, can't ever justify the spending really but what the hell life's for living!) then go for it mate, get the stock and then work longer on accessing who the culprit was. Tiger barbs have a bad rep for being nippy, yours have been cannabilistic so that can only lean towards being all out butchers of other species
I was thinking it was a possibility once I saw little worm like , possible parasites, crawling around him. And it wasn't long after he was dead.Try Jeff Rapps, thats where I orderd my two from. Still battling a serious case of ich though. Some part of me still thinks bacterial infection may be involved.