Strange Tank Event

[Donya]

Well, I don't know what happened in the early hours of the morning between 2am and 6am...add one to the list of near-disasters with my 12 gallon. I woke up to see my CBS perched on the filter sitting completely still in a threat posture towards something. It wasn't moving...in fact, it was stiff as a board when I bumped it off the filter (like rigid paralysis). I also found my conches looking distressed and there were worms crawling out of the substrate in large numbers from one spot in the substrate. Although the shrimp went opaque and limp while I did a 40% water change, I revived it with enough air being pumped into the water and it's back to moving around and being transparent. All this time, my turbo snail and one fish were perfectly fine.

The water prior to the WC was:
1.026sg (a little higher than the tank usually runs)
8.40 pH
trace ammonia (this was new)
0 nitrate
0 nitrate

The stats are mostly the same now except for ammonia, which is not reading anything. The trace amount of ammonia was the only thing I could see that would cause such a response...but, I only had trace nitrite as an indicator when my 12g was seriously nuked the first time around. I dug around in the substrate in the area where stuff seemed to be evacuating, but I couldn't find anything...is it possible something big died in the substrate and deteriorated so fast that it's not there anymore? I know echinoderms are known for that, but I only have really small starfish in my tank...couldn't find any culprits for a nuking elsewhere in the tank.

Also, more importantly, should I continue to do large water changes in case there is some toxin in the water? If so, how long should I wait before I do the next one? I was figuring that since most changes are only 10%, I should probably wait until at least tomorrow to do another one since, at present anyway, everything seems to be improving rather than deteriorating.

 

[rhysiboy]

maybe a mantis shrimp came out to play and attacked something

 

[Donya]

Attacked what though? All of my animals were physically in tact...which wasn't the case the last time I had a mantis make an appearance. I lost the CBS late last night due to continued gill problems after the initial recovery, but nothing looked ripped up, smashed, etc.

 

[rhysiboy]

hmmmm well my guess is there is something (havnt a clue what) that is hiding somewhere that seems to be a bully. maybe it was coz the shrimp was asleep and it was shocked -> stress-> death. that would also cause all the other worms and crap to move because they would be scared by the sudden movement of the shrimp.

(im probably speaking rubbish though chek with others on what it is that could be doing it)

althoug the CBS could of had a fit

 

[SkiFletch]

Dunno how to explain that Donya, perhaps a sandbed creature bit it and released some toxins . Did you consider exterior stresses? Perfumes/colognes, hair sprays, any airborne cleaners? Or perhaps nearby roadwork/housework leading to strange vibrations? Sorta grasping at straws here

 

[Donya]

There was an uncapped marker for a while that smelled a bit (nontoxic though, and I capped it when I realized it was open)...that is the only thing I can come up with environmentally. But, it was right next to my 1 gallon, which suffered no ill effects, and pretty far away from the 12g.

After loosing the shrimp, I lost my largest conch this evening. The conch's death may be unrelated, since it was showing signs of snaily old age for about a month (not making that up btw--seems to be a common set of behaviors & changes in aquatic snails), but I can't help wondering. Everything else in all tanks is 100% ok. I did another water change, params are fine. Of course, the brisleworms are already seizing the day with the CBS gone. They've forced my anemone off its rock already. Not a good couple days