Mysterious death of Silverbarb fish

[metagirl]

Was at a friend's house the other night when we unfortunately, got to watch one of their silverbarb fish violently die. we were told that this was the last fish out of 4 silverbarb that had died within the last few days. me and husband guessed that it must be the batch of new food they are using - but none of their other fish have died (they are of a different variety). They believe it isn't the food, but could be that the first death had a knock on effect on the others. Loneliness? Depression? They had the fish close to 9 months. Any ideas?

[brachiopod]

Not sure what species your friend's 'silver barb' is (or rather, was) - whether it's a true barb (ie a member of the genus Barbus) - it sounds a bit of a general name, as I haven't heard of it as a common aquarium fish in the UK. (There is a 'silver barb' Barbodes gonionotus that is raised as a food fish in Bangladesh - usually in association with freshwater prawns.)

Anyway, my point in asking is that some other barbs, like Tiger Barbs (Barbus tetrazona), and Ruby-headed Barbs (B.nigrofasciatus) are quite sensitive to nitrite levels in the tank and tend to invert themselves and do a strange 'head-standing swimming-on-the-spot' type thing.

Not sure exactly what the fish in question did before they died, but if it was anything similar, it may be worth checking the water chemistry for nitrite. (Most testing kits will test the levels of nitrate and ammonia aswell).

Let us know how you (your friends) get on.

[metagirl]

thanks for that. I don't know any more detail about the kind of fish - but as they kicked the bucket they did do a funny - well not funny, more like extremely violent - thrash dance. Will tell them about the nitrate thing.