Devastated, 4 Dead Fish. Please Help

[indigoj]

Not having a fun week... Having lost 2 platies to a sudden and mystery illness earlier in the week I got up this morning and have lost 4 more fish with another looking decidedly 'not right'

I've lost 2 baby spiney eels - one we had not seen for 24 hours, the other had been eating last night and seemed fine.
1 Featherfin Catfish (very young), had not been seen much but was well and swimming 12 hours earlier, and the slightly older Featherfin was swimming at the top of the tank not looking good but we have pulled him/her into the q-tank along with a baby Gibby.
The other baby Gibbiceps, again was seen last night apparently healthy, eating and with no obvious signs of disease but also died.

This is my well established tank and we water test every 2-3 days. Water stats which were tested 2 days ago were fine, 0 ammonia, 0 nitrite, 5 nitrate, ph 7.2 are now 0.4 ammonia, 0.8 nitrate, 10 nitrate and worryingly the ph is 5?!!

The only additives in the tank were dechlorinator, 1 tablespoon of aquarium salt - this went in days ago though and we have done 2 water changes since then, half dose of melafix and half dose of primafix (the gibbys had been a bit territorial and the platies we lost were in this tank so these were a precaution.) The 4 other platies are fine (even pregnant)

105l tank, regular water changes, fish fed on bloodworm, flake, algae wafers and catfish pellets.

HELP don't want to lose more fish

Could it be my new dechlorinator? Anyone heard of this happening? It is a shops own brand.

 

[scooterchick]

Hi there,

You seem to covered everything and if the only thing that is different is the de-chlorinator then I guess you have to assume thats what it is. Out of interest have you tested your tap water? Perhaps that's what's changed.

If the tap water is ok, I'd get another bottle of de-chlorinator (what you normally use) and do a substantial water change. I think I'd probably treated for internal bacteria too.

Also give your filters a good check in case there's fish 'waste' stuck in them.

HTH

And please if anyone thinks they shouldn't be treated for internal bac, please say so. It's what I'd do but I'm not as experienced as some others.

 

[-germ-]

Possibly Old Tank Syndrome although i don't know a great about it, i'd be inclined toward this because of the sudden drop in PH, but having read little on the subject i'm not sure if the drop would be have been so sudden.....
In fact i'd always thought it was an extremely slow process, but like i say i can't confirm this so maybe its worth you looking into the specifics?
Or maybe who understands the process a little better can enlighten me?

I'd agree that the DeChlor sounds fairly iffy aswell, you should ask them for a run-down of the components involved.
Do they advertise the product on a site?

 

[corey01]

i guess it was the sudden PH fluctuation that killed some of your fish but the question is what caused it?!
the only thing i can think of is testing your tap water .

 

[indigoj]

Tested tap water, that is fine at ph7.2 which is normal for here and the same as tested previously.

While I agree the dechlorinator seems a likely culprit I'm now not sure.

I have just tested my q-tank and my newer tank and while the ph is around 5/5.5 in both of those the fish are unaffected... even the Featherfin Catfish and Gibby from the 'Tank Of Death' seem to be doing better. The temperature in the q-tank and newer tank is at around 27-28 degrees while the tank of death is at 24... Don't know if this is making a difference.

BTW, the q-tank houses my platies including 4 month old fry - all ok, the new tank has 6 Praecox Rainbowfish, 6 Tiger Barbs and 3 Albino Corys - all fine, Tank of Death still has my Gouramis in who seem fine too....

Baffled!

 

[scooterchick]

Have you introduced any new fish recently? (Although this wouldn't account for the drop in PH)

 

[indigoj]

Germ,

I found an interesting article on Old Tank Syndrome which does suggest in some conditions it can happen quickly causing a PH crash...

I am now wondering if the Dechlorinator (which having conducted some tests does seem to lower PH but from 7.2 to about 6.5, not to 5 - won't be using it again) has sped up the crash... Which in my established tank would affect the more delicate fish but in my new tank could be helping because a low ph holds ammonia in a detoxified state.... Hmmm

http/www.bestfish.com/oldtank.html

Worrying if the low ph kills off filter bacteria though....

AAAAAAAAAAARRRRRRRRRRRRRRRRRGGGGGGGGGGGHHHHHHHHHH

 

[-germ-]

Yes, from what (i think) i remember the low PH kills off your filter bacteria yet perversly also renders it practically non toxic.