Cause of Death?

[Moloch]

I have a 65g tank with a rena xp3.

2x senegal bichir
1x jack dempsey
2x (female) convict
8 (now 7)x tiger barb
1x african dwarf frog (feeder, stayin alive)
1x mystery snail

I did a 50% water change this morning. Water was getting a little cloudy and brown from my driftwood leeching the last of its tannins. So I vacuumed the sand like always, drained half the tank with the filter & heater off. I fill using a python, so I got my tap water to the same temp as the tank (like always) and let her go. Once full I dosed all 60ish gallons with prime (as opposed to only dosing for the 30 or so new gallons) and moved on to start the WC in my 20gal... and then I noticed one of my tiger barbs.

Its the smallest barb in the tank, not quite an inch long. He was sort of drifting in the current, barely making an effort to swim. Eventually he settled to the bottom of the tank and began having little spurts of life. He would dart up and swim tight & fast corkscrews (clearly out of control) before settling back on the bottom.

Presently the barb is becoming food for my convicts & dempsey, but I'm wondering what caused the untimely death? None of my other fish seem phased at all. The barbs are acting a TINY bit funny...they aren't as active as usual and for the most part seem to be hanging out by the heater. Usually they're all over the tank.

What might I have done?

 

[Moloch]

Came back from an afternoon out and now #2 is dead...down to 6 barbs.

I'm wondering if they're just starting to get picked off by the JD or the bichirs or something... I see no other signs of ANYTHING with the other fish, they all seem quite content, although the barbs are a little more spread out than usual now.

 

[NCStateFisher]

sorry to hear that... when you listed off your whole stock at the start of this article you scared the hell out of me, i thought all your fish died =X

 

[Moloch]

haha, nope, just two. Every fish in the tank has been eating away happily at the carcasses though. Fish = cannibals. They're almost completely gone.

I'm thinking I might replace them tomorrow...I've noticed the barbs getting a little more nippy towards eachother since 'the incident' ....



I'm thinking they either got attacked when I wasn't looking, or the stress of a 50% water change just did them in. Strange though that one died right after the WC and one died somewhere between 1 & 4-5 hours after the wc.

Who knows...the rest of the fish seem healthy so I'm not too worried about it.

 

[NCStateFisher]

yeah as long as your core fish are okay that's gotta be the major concern, my silver dollar school has ironically been reduced from 8 to 6 as well, the smallest one was incredibly stupid and swam under the filter sideways, got stuck, i got him off not too much damage, i looked over about 5 minutes later and watched as he swam headfirst up the filter, got his eyes sucked out of his head - natural selection at it's finest. and then I have one now that is quarantined because he isn't acting right, he doesn't school with the other fish and is very lethargic. I'm not willing to risk the health of my 6 bigger SDs my 2 gourami's and 2 bichirs for one small unhealthy SD. I'm all for drying to rehab fish but he won't be going back in that tank unless he shows some serious signs of improvement.