our big redeye tetra is no more!!!

[millym]

hi
had an unexplained death in our tank yesterday. found one of our redeye tetras dead floating in the tank - had no signs of any diseases all our other fish look/act fine
water : ammonia 0, nitrite0, nitrate 10, pH8 (our ph is always 8)
what could have caused it??? stroke? heart attack? plain old age we've had him/her for about 5 months & he was a big bugger for a red eye about 3 times the size of 2 of our others. i saw him swimming happily in the morning & in the evening he was gone quite sad really & a bit mystifying.
we've got a cae that we know we have to take back to the lfs before he gets nasty could he have done something??? what does a fish look like when its had its slime coat sucked off??? as we've heard this is what cae's do when mature & they get territorial.
any hints??clues?? most appreciated. we know we have to return our cae vv soon but havent had the heart to do it yet, maybe we've made a big mistake.

 

[Angel03]

So sorry to hear off your loss , ive had myterious deaths to , it is very confuseing when you don't know what they passed with

 

[big G]

I 2 had a big boy redeye tet and he started 2 get alarmingly big towards the end. It turned out 2 b dropsy ! balloon & pop spring 2 mind , shame . ur situation is different though . were there any singhs of fins/tail damage due 2 biteing , if not then it truely is a mistery ?