Suddenly Ill Cobra Endler Guppies

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Frank_Jon

Aquarium Advice Newbie
Joined
Jul 31, 2016
Messages
2
Hello,

I have 2 male Cobra Endler guppies that were very happy and healthy until two nights ago (Saturday). I did two 50% water changes on Saturday (the second one was to pick up additional algae after an outbreak this week), and since then they've been moving their mouths rapidly, extremely lethargic, timid, and sleeping at the surface. They also mostly ignore their food.

Since then I did two water changes yesterday (Sunday) and a 25% water change this morning. Each time the new water seems to revive them, and then they slowly worsen hours later.

Ammonia and nitrates are at 0. pH is 7.6, although I noticed yesterday it was rapidly dipping to 6.4, so I removed the piece of driftwood. (The driftwood had been in there for over a month, so I don't know if that was the culprit affecting pH. The only difference this time is that I scrubbed it with a toothbrush before putting back in tank.) Temperature is consistently 80 degrees.

The tank is a 2.6G Fluval Spec III. It is heavily planted, and ordinarily I do a 50% change weekly with new, treated water. The tank was cycled for 2 weeks and has been going for 2 months now. The pair in there now have been healthy and happy for about a month.

I don't know the filter name, but it's the one that comes with the Spec III. It advertises 46-66G gph; although, the previous owner punched holes in the tubing to slow it down. I found it to be too slow, not causing enough surface agitation, so I wrapped most of the holes in Gorilla Tape. Agitation now seems very good. (I know I took a risk with the Gorilla Tape, but it didn't seem to impact the fishies when I originally added it.)

The Endler guppies are about an inch each. There is also a Nerite snail in there, who seems fine (that guy's a pig).

Before they got ill, I had changed the activated carbon insert, but forgot to rinse it first. I realized this on Sunday, hence why I've been so aggressive with the water changes. That was the only change I can think of from what I'd ordinarily do.

They eat Top Fin Color Enhancing Tropical Flakes (crushed very small). I usually feed them once daily. The day they became ill was a "fast day" for them.

Thank you for your help!
 
Hi, welcome to the forum :)


I'd keep doing the water changes imo. I'm wondering what your ph is normally? If it is dropping quickly that might indicate a lot of bacterial / algal activity which would use oxygen so I would also increase tank aeration as well if you can. Is the tank water back to clear now? No green or white cloudiness to it?
 
Delapool - I think you were right about the bacteria....

Update: After a few more changes, I honed in on the API StressZyme as the culprit. I had been overdosing them given the extremely small tank (pouring it directly in instead of using the dosing cap). I read in one other forum that an overdose of StressZyme can cause a pH crash, and that appears to be true. Problem solved!
 
Sounds grand! Hope the tank goes well. I had thought canister filter sludge had been reduced using it (in a cycled tank) so could well see it doing something more than normal.
 
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