Why Crabs And Not Snails?

Why do people buy so many carbs as a clean up crew but only use snails as a algae eater? Tonight I witnessed a astrea snail that had fallen from the glass eaten. The few crabs I have in my tank ran over to it and started to eat it when it was almost dead. After only a few minutes my tongan dove tail snails came out to help. The tdt snails (4 of the 6 I have) ate the dead snail in about 5 minutes. Before I had the tdt snails I had a few astrea snails die and the crabs worked on them for almost 6 hours. Don't you want the dead stuff out of your tank quickly?

Why would you want crabs that knock and turn stuff over and fight when you can have faster more reef friendly snails? I don't think I will ever buy a crab again unless it is a decrative pet and not part of the clean up crew. How many tdt snails will a 55 gallon reef support before they will starve?

Hello everyone,

Mark Peterson wrote: I've never heard of TDT snails. I'm intrigued by your description. Are they available locally?

Sure you have. Tongan Dove Tail, I gave you one a little while back. Over the last few months I've seen them in at several of our local shops. TPF and MA are two off the top of my head.

Chris wrote: Why do people buy so many carbs as a clean up crew but only use snails as a algae eater?

Where to begin.. First of all, some people do use snails as a scavenger component in their clean up crew. There are a variety of nassarius snails (TDT is also a nassarius) that people use to scavenge for extra food and dead animals. The most common nassarius used is the vibex variety. Vibex is often the first choice because of its specialized diet and small size. Other nassarius, like the obsoleta, have a less specialized diet and are more likely to exhibit predatory tendencies. I haven't been able to find very much reliable info specifically about the TDT snails. Because of this I'm going to err on the safe side and assume they're going to eat anything meaty. Which of course could easily include a variety of beneficial worms, etc. Obviously, this isn't necessarily a fact and is only based on general facts about nassarius snails. 

Chris wrote: Don't you want the dead stuff out of your tank quickly?

Sure do. How slow is too slow? I don't know. FWIW, the BWs in my tank are on dead material instantly and do an incredible job of making everything disappear.

Chris wrote: Why would you want crabs that knock and turn stuff over and fight when you can have faster more reef friendly snails?

I've been wondering that for years. However, my reasons focus more on thier omnivirous diet and predatory nature. You've seen my tank and obviously they're not necessary. Unfortunately, every vendor you ask will tell you that you NEED 1+hermits/gallon. Gee, I wonder why...

Chris wrote: How many tdt snails will a 55 gallon reef support before they will starve?

The answer depends largely on how much you over-feed your tank. In your tank I suspect that 5 TDT snails account for more mass than your fish. Excluding the tang of course because of it's completely different diet.

To keep them alive and happy you're probably going to have to feed them specifically. Which of course defeats the purpose of having them there to clean up the extra.

IMO, 5 vibex would be plenty for your tank and 5 TDT is serious overkill. Personally, I would recommend one or less TDTs for your tank. In that way it will function more as a clean up component and less like another animal you have to feed.

Hope that helps,

Chris

Hello everyone,

Chris wrote: What if my sand bed is not used as a filter but more for ground cover?

Ok, that changes things. Now we're talking about a situation where you probably don't want "stuff" to be/or accumulate, like a berlin system.

Chris wrote: And what about the fish (red scooter blenny) that sift the sand for food don't they cause the same massive disturbances if not more massive?

The blenny picks through the sand for critters. Ya, that's not good for the bed, but in a different way. The snails are digging inch+ deep holes. It's the burrowing that interferes with the dentrification process and kicks "stuff" into the water.

Hope that helps,

Chris

Hello everyone,

Mark Peterson wrote: Was that the one that is about an inch long that I found the other day when looking for Cerith snails in the substrate.

I bet it is. About an inch long, mostly a white/cream color shell with a very white body. It also has an extra small patch of shell on its tail. Very cool looking snails IMO.

Mark Peterson wrote: Would a shallow sand bed have enough food for the predatory snails and would they then prey on Astrea Snails that fall but could have recovered if given the chance?

FWIW, I suspect the hermits made the first strike ripping open the astreas flesh. The TDT then responded and made quick work of the wounded animal. I doubt a TDT would take down an astrea as a first choice,.. But as you've suggested, what happens when thier preffered food supply is exhausted? How hungry will they get before potentially resorting to predation? I don't know. Just remember, they're not eating algae.

Hope that helps,

Chris