Dying Snails.

[Jason Donohoe]

I am having trouble keeping snails alive in my tank.

The specifics

72G bowfront with 25G sump/refugium
sg 1.026, temp 80F, nitrates and phosphates zero
The tank has been up and running for about 4 years. I slacked off and it went to pot for about 2 years during that time. Cleaned up my act and the tank in August.

Current inhabitants include 2 small emerald crabs, 8 red legged hermits, cleaner shrimp, banded serpeant star, short spined urchin, 3 nassirus snails (that I have seen recently) and 1 zebra trochus snail. The tank is mostly softies with 1 hammer coral. Lightly stocked with 1 small yellow tang, blue damsel and perc clown.

All the corals and fish are doing great. All the crabs and the shrimp are doing great. They have been in the tank for about 4 months. The serpeant star and urchin were just added 2 days ago. The serpeant star has disappeared into the rockwork and the urchin has been quite mobile at night.

The problem is the snails. I started 4 months ago with 6 nassirus snails and have found 2 empty shells in the last month. I also don't see them out as frequently at feeding time. I tried astrea snails, they did fine for about a month and then all died over about a week. Ditto for nerite snails. I added 8 zebra trochus snails after the rest had died. They have gradually died over the last 2 months. The crabs were added at the same time as the trochus snails so I can't blame the early snail deaths on them. I currently have a trochus snail laying foot up in the sand so I don't think the hermits got him either. I had one trochus in the refugium with lots of algae and no crabs, now he's an empty shell.

I have heard that very low copper levels can be toxic to snails but undetectable with most tests. I have been running carbon consistently for the last month and am planning on adding a 2 stage DI to my RO in case I am getting copper from the pipes.

It was suggested from a fellow reefer that stray voltage may be an issue. I don't currently have a ground probe.

Sorry for the long post but I read a number of other threads before posting and tried to answer all the questions raised in them.

Would a ground probe be of any benefit?

Are there species of snails that may have better longevity than the ones I have tried?

Any other thoughts?

Thanks.

 

[dendro982]

I may be not much of help, but it shouldn't be copper - I'm using tap water from copper pipes (Cu test shows undetectable levels).
Just to be sure you can try (if you can) Cupramine or Toxic Metals Sponge.

Grounding probe may, or may not help, but wouldn't hurt: maybe you already have in household stainless steel wire from hardware store and heat shrinkable tube from electronic store, and a single plug (to insert into 3rd, round, grounded socket) from either of these stores. DIY grounding probe worked for me - I have too many tanks to buy $20+ grounding probe for each of them

What I could think about:
- Hermit crabs, if they are medium-large, may have a problem with snails, puffers and triggers - too. For me, crabs eliminated astreas, and toby puffer - a couple of Mexican turbo snails.
- Nerite snails died by themselves for me too, I had read that they are tidal, and even shallow 6" tank didn't help, ceriths too, but nassarius survive even in bare bottom tank. Astreas, trochus, and zebra turbo (2"!) without predators last at least for a couple of years, zebra is already 3 yrs. old.
- Maybe toxins of red slime, or dinoflagellates, or flatworms killed them? Or unnoticed ammonia spike (snail, laying foot up, makes think of it), corals look depressed after that. Aging DSB comes in mind, but I have BB tanks, can't say. You have no sulfur denitrificator, right? Bryopsis or other indigestible algae, they theoretically shouldn't eat wrong kind, but who knows.

Zebra turbo, trocus, astreas, nassarius are quite durable (hardy?) even in my antisanitary conditions (non-photosynthetic and filter feeders tanks without high-end skimmers).
HTH

 

[Jason Donohoe]

Thanks for the input. I am already planning on adding the DI unit so after a few water changes any copper should be diluted out a fair bit. I think I will add the grounding probe and try again with some trochus snails.