Lost a couple fish last night...

[JeanR]

Earlier this week I noticed some cyanobacteria growing so I treated with Chemiclean, waited 48hrs and did a 30% water change. I have a 30g RSM mixed reef and I get some cyano growth every 4-6 months or so and just treat it with WC (and chemiclean when WC not enough).

Last night I turned off my pumps (return pump and MP10), spot fed my corals with reef roids/etc, turned the MP10 back on. Usually I leave it like this for an hour or so and then turn my return pump back on.

I forgot to turn my return pump on before going to bed and woke up this morning to 3 dead fish (royal gramma, clown fish, scooter blenny) and a dead feather duster. Other fish were gaping, but after turning on the return pump now appear to be fine (watchman goby, clown goby, 2 mandarins, 2 blue stripe pipefish, firefish).

I have forgotten to turn off the return pump after a coral feeding before, but this has never caused any fish to die.

Any idea why my missing the return pump was lethal this time?

 

[Chris A.]

How many fish did you have total?
If the water top wasn’t getting agitated they could deplete the oxygen in the tank pretty quickly without a skimmer, also how cold did the tank get?

 

[JeanR]

Had 10 fish total, probably a bit high for a 30g. Don't know the exact temperature as thermometer is in the sump, but likely didn't fluctuate much.

I think your right regarding the oxygen. Chemiclean can also deplete oxygen. Am wondering if I still had some residual chemiclean in the system and the combination of that and my return pump just pushed everything off the cliff.

 

[dz6t]

May be change the return pump to a small DC pump? DC pump has feed mode that will prevent this happens again.

 

[dz6t]

I carry this tiny DC DCS-2000 return pump that has smaller foot print than a portable hard drive

Sent from my iPhone using Tapatalk

 

[Zirky]

The chemiclean label sayes it deprives water of oxygen. I used to run my skimmer without the cup when I'd treat cyano.

 

[gurumasta]

I agree mix of Chemiclean and not enough water agitation from the return that the oxygen was depleted.. Sorry to hear Jean that sucks..