sad sad first attempt


New member
I've been interested in mantis shrimps for a long while now and finally set up a small tank for one. I bought an 11 gallon via aqua tank w/ a power compact light perfect for nano-reefs. jury-rigged a lifeguard FB300 fluidized bed filter onto it and cycled the tank. when the tank was ready I put a small pistol shrimp in and he was happy. a week later nitrates were still very low so I added a few very small green mushrooms to the rock. I originally wanted to get a squilla type spearer mantis but to date have only seen one once in a shop, so I settled for a huge 6+ in. O. scylaris that cost way too much and had those brownish sun-burn sores on it's telson. it shed the skin within a week and seemed happy, but reluctant to accept any food. the color was decidedly yellowish green but the sores were gone, with only a little remaining marrs. he only accepted goldfish if I persistently shoved them in his face and even then reluctantly. the store I bought it from (aquarium city) said he scarfed on red fiddler crabs, but that wasn't the case in my tank. this morning i tested pH, ammonia, nitrites, salinity, nitrates, and kH. ph was a little low, ammonia nitrites, and nitrates were all 0, even after slight adjustment last night salinity was slightly high, and kH was fine. tonight about 9:00 the mantis was on it's back feet out and slowly moving it's swimmerets, the red fiddler crab was way up high on a rock next to dead, the pistol was dead. larger isopods were all dead and within an hour the mantis retired into it's hole to die. commesal crabs on a turtle weed rock were also dead, but smaller copepods were all seemingly fine though. also minescule (like almost ich size) white critters were all over the glass towards the top, having a field day. I'm sorry this was long winded but I'm at a loss here. any reason all large inverts in a tank would die?
no, it was fully cycled before any critters were put inside. i was sure ammonia and nitrites were 0. besides, the filter is supposed to be sufficient for a 300 gallon tank and it's on an 11. the morning of my disaster, ammo 'ites and 'ates were next to 0 so it couldn't be that. but thanks for the suggestion
not a chance, i added in some AmQuel the night before, because i put in some top off water, that should get rid of any heavy metals that possibly snuck in, i also run the tap for 6-7 mins before actually collecting any, to be sure copper from pipes isn't in the water

on thing comes to mind though... it is an open top tank and household chemicals could have easily been oversprayed, but i am not ever in the mood to clean, and no one has been in the house besides me for the past few days. I am at a loss
Using tap water may be in question, chlorine? AmQuel is a ammonia reducer, may not take out all impurities from tap water.
Are you using city water or well water? Either way R/O water is the best, and having to use tap water I'd get a good dechlorintor.

What's a Turtle Weed Rock? Anything new in the tank that could be contaminated? Clean anything with any household cleaners?

Losing all your inverts sounds like contamination: Water, objects....
thanks for all the replys! you're right i'm probably the only person wh can figure out what happened in the tank, and for a future reference i'm moving the tank to a lower traffic spot and fabricating a cover to keep out possible contaminants. also i was recomended to use "poly filter" to remove any impurities when my tank's inhabitants look bad (hopefully won't happen again) I was using local tap water and yeah AmQuell really only takes out Ammonia Chlorine and Chloramines. Turtle weed is also known as maiden's hair and is a bright green slow to spread hair algae w/ commensal crabs (not any more). again thanks for the suggestions. BTW I requested a spearer from a local store and they said it would be possible to get a yellow one in this time of year, is that a cilliata most likely?
I just recently aquired a Clown Mantis too and they guys at two different fish stores said that a mantis could survive the cycling of a tank easily. They both said using reverse osmosis water would be a waste of money. Anyway i did a pH check and ammonia check and needless to say they weren't good. But the mantis seem to be fine and healthy he eats his daily rations of freez dried krill eagerly. At night he roams around and throught the day he looks at everything and is alert. Seeing this post worries me. If he has been doing good for a week and a half should i have any concerns. I just did a water change. I would appreciate any replies thanks
Sorry to butt in, I have no personal experience of any kind just something I read yesterday that those creatures are so sensitive that even something as innocent as waxing a floor near a mantis tank can kill them. Maybe you took 100% perfect care of the water quality and just something in the house near the tank got them sick?

I recently had new vinyl laid and the seam sealer stench was powerful enough to make me feel loopy so I am certain any mantis (if I'd had some) would have assumed the dead cockroach position :(

Could it be?

Just something I read, as I said, I have no experience. Just love lurking on this interesting forum and read.

Again, hope no one took offense at my posting.
no offense at all, everyone that i spoke to mirrored your reply, i recently soaked a polyfilter in the water for 2 days after doing a partial (5 gallon) water change then added 1/4 a bottle of fritz-zyme. the water should be sparkling clean by now. thanks