This is not intended to be nothing more than a post with my limited knowledge in FW Clams and Oscars.
I got four FW clams from the LFS. One of them died in the bag. I am not sure of the species I am keeping. They passed quarantine in the LFS and the owner, with whom I do have respectful disagreements, at least is one of the LFS that would give good advice in compatible tankmates to his clients' wish-lists (like don't put Oscars and Midas together). A rarity at least in my City's LFS where common sales practices include that Rainbow Sharks are offered in pairs to be kept in the same tank, usually a 10gal starting kit.
So I can trust this clams to be healthy.
FW clams are not a good idea for a beginner. They require a well established tank, in which micro-flora and micro-fauna already exists. Since my Oscar tank is rich in detritus (food debris, dissolved Indian Almond Tree Leaves, decaying leaves, and even some algae) I figured this could work out. So far it's been OK. My Oscars, shown curiosity upon their introduction but no attack on them was attempted (so far).
If you aim at a crystal clear tank, then FW clams is not for you. Ideal filtration for FW clams is likely a compromise of enhanced bio-logical filtration and somewhat diminished mechanical filtration. The spot where FW clams are to be located, should contain sand or a mixture of sand and small sized gravel, with mild to moderate internal currents of water passing by. A dead spot should be avoided since the clams could starve to death.
There is some controversy about the potential harm of FW clams to fish. In nature, most FW clams have a complex life cycle. In one of its developmental stages, called parasitic larvae or glochidia they attach to tissue of a host fish; whether or not this is true parasitic phenomenae isn't at all clear, but the glochidia actually feeds on fluids from the host fish. A cyst, that resembles ick but is likely bigger, observable through the naked-eye, can be considered evidence of this stage. Characyns (e.g. Silver Dollars) have been documented as host fish for some FW Clam species. I found no evidence of Cichlids in this role (which might be due to lack of published studies regarding Cichlids and FW clams,not the fact that they are not candidates for host fish).
In nature, most host fish suffer no life-threatening risk, but in aquarium tank, the story could be another one. The major risk, so far the most commonly found by me in a limited websearch, is related to foul tanks due to unnoticed dead FW clam(s). These invertebrates, although interesting to keep, will end up buried in the substrate, and they do move around from time to time.
Handling them with care, once settled in your tank is another issue to keep in mind. When doing maintenance, the first thing I do is confirm where they are so I avoid disturbing them, or carefully remove them if I need to work where they are (which is how I ended up with the video of FW clams mating). They may look hardy, but truth is, that unlike SW clams, the shells of FW are way more fragile. I figure it has to do with FW carbonate and general hardness being lower than in saltwater tanks, as well as the mineral contents of substrate used in tanks.
I used clear epoxy to fix a big hole in one of my FW clams. I removed the clam upon noticing this, the absence of bad smell (they do smell terrible when dead) encouraged me to try to save this specimen. I used the finest sand paper I had available, cleaned the area around the hole and applied Epoxy after three minutes of mixing so liquified epoxy wouldn't drip inside. I placed the clam in a shallow water so the epoxy had time to cure. I took time to be certain it was alive before placing this one back into the tank.
I am amazed by the price of this living creatures in the web. These are sold at USD2.75 locally, as adult individuals.
Pepe
Santo Domingo
