A properly functioning tank or cycled one will have 0 ammonia and 0 nitrites, and 20PPM maybe a little higher. If your shrimp (RCS) are dying as well, it is because when the clam dies it cause a ammonia spike and your shrimp die. Ghost shrimp may not be effected because they can live in anything.
Like stated above and in other post we are trying to help you not have experiences we have had. We are also looking out for the other critters in your tank you keep, as well as you spending money on something not suited really for fish tank. If you want to keep doing trial and error experiments go for it, but be polite and just put the clams in the tank and spare all else from your experiments. Trying to keep something that ends up killing others is torment to the other critters while this happens.
Nothing else has died as a result of the clam deaths. We had RCS at one time. But they all died before I bought the clams. The otos died while the clams were all accounted for. The betta and ghost shrimp haven't been bothered in the least despite being present for all the clam deaths.
Originally Posted by lochaber
I think this is a combination of several factors:
1. clams aren't terribly active. They don't up and jog around the tank much. For a lot of people, that's how they distinguish twixt dead and living. It just makes it a bit more difficult to notice if a clam dies - you have to be specifically paying attention and looking for signs of life (or lack thereof).
2. They tend to be buried in the substrate. This compounds the above problem.
3. Clams have a pretty significant mass of flesh/tissue for their 'size'. - they aren't quite spherical, but pretty close. a clam 1" wide/long probably has quite a bit more flesh then a fish that's 1" long.
4. And I suspect their shells may make it more difficult for potential scavengers (snails) to take care of them before they decompose.
Anyways, I'm not saying it's impossible to keep them, I just think it's pretty risky, and the typical home aquarium isn't the right setup for them. On the other hand, I have a vague memory of someone 'finding' a living clam in their aquarium during some rescaping or something. I can't remember where I had seen it, I wish I could...
1. My experience is that it is rather simple to tell when a clam is dead. They only open their shells to feed. Even then the shells only open slightly. Clams have to work to keep their shell closed. So a shell that's open wider than usual is a sign of trouble. If you poke it and it doesn't "clam up" (the origin of the expression) then you know for certain it is dead.
2. They don't bury themselves completely out of sight. They have to stay slightly exposed in order to feed. Only one of our six clams even bothered to bury itself at all. A clam that has fully buried itself has only done so out of stress. It is hiding from something. Even slightly exposed they are definitely difficult to spot. But they don't move much at all. So once you've found them in a certain location you can be fairly certain it is still in that area even if you don't actually see it. Having a densely planted tank also makes them a bit harder to find. I'll agree that you do have to strain a bit initially to locate them. But after a while you just know where they are.
3. I think I agree with this. Having seen a few dead clams now they do seem as though they might be a bit more fleshy than a fish. I don't think it's a huge difference though.
4. Going back to point number one, a dead clam will have an open shell. It is a simple matter for smaller shrimp to crawl in and do their thing. I saw a video of exactly that somewhere while I was researching the idea. I have yet to see our shrimp scavenging a clam. But I haven't left a dead clam in the tank long enough for them to notice yet. That's the latest experiment. Clam #5 died this morning. I fully opened the shell to see if the shrimp and cories would find it appetizing.
I'm not trying to be difficult about this. The one thing that annoys me about this hobby is that it is rife with folklore and hearsay. The epitome of this is a post I read the other day in which the commenter warned people that dirt is a bad substrate choice because it releases "toxious" gasses that could cause serious health problems if you happened to be leaning over the tank at the time a bubble of these gasses was released. Clams just aren't common enough that a lot of people have experience with them. So when I repeatedly read the same comments about them I have to wonder where the information comes from. And when the comments don't jive with what I've seen firsthand I have to question the validity of them.
In the interest of science I just set up a 1.5-gallon desktop tank. Its primary purpose is to house daphnia as a treat for our betta. But I also plan to use it to see what I can do with clams. Once the tank is cycled and stabilized I will move our remaining clam to it. Then I'll begin experimenting with foods and studying the clam's behavior to see what I can learn. I'm doing this mainly to satisfy my own curiosity. But I also want to get away from the folklore and see what the truth is. If that ends up making me a guru, so be it.
At this moment I have no plans to add clams to future tanks. I need to gather information from the research tank first. And I've found a much more intriguing filter feeder to help clean up our betta tank, bamboo shrimp. As I type this, one of our new bamboo shrimp is downstream of the dead clam happily filtering detritus out of the current.