Dear Mr. Goemans,
It has been some time since I have sent you an email, and you were very helpful. I've setup my new 150 gallon tank just like the first one and everything is going fine, except I have a clarke clown who is a monster, as it digs holes and bites me, and I mean bites every time I go to clean the tank. I call him Garfield, because when he looks at me, he reminds me of Garfield the cat.
This is not the real subject of this message, as I 'had' 6 Tridacna clams, Crocea and Squamosa. A couple of weeks ago I noticed that one started to spawn and the others followed one by one, except the larges Squamosa and a juvenile. I had raised the baby from a size of an almond to the size of a chicken egg. This spawning went on for a couple of days, then by the third day they started to die one by one except the large one that did not spawn, and the baby which did not of course spawn. I have the Daniel Knop book on Giant Clams and I checked my water temperature and salinity, which have been the same ever since I've had them starting about 2 years ago. I also checked for other things he mentioned and could not find any evidence as to the reason for die-off. I am stumped! Why should this start right after spawning? Have you ever hear of this problem happening before? Would love to hear what you think.
Thank you very much.
Sharon Moore Diamondhead, Mississippi
Thanks for your letter and as for your clams, the worst possible thing for clam health in a hobbyist aquarium 'is' spawning! In fact, if you don't quickly clean up the spawn, eggs and/or sperm, the water quality will 'quickly' deteriorate since they all rot at the same time. And that 'quickly' occurs, as the spawn begin to die within one hour or less! Their deterioration causes a dissolved oxygen drop in the aquarium, and then other various organisms begin to die. And besides the oxygen drop, ammonia begins to elevate, another possible cause of death.
It's already too late in your aquarium, but do recommend major water changes to get water quality back on track before unwanted algae becomes a major problem. Also vacuum as much of the substrate as possible. Do a very good cleaning job! And in the future, when spawning occurs, remove that spawning clam and place it in a holding tank until the spawning ceases, then place it back in the main system.
Hope this helps,
Thank you so much for the fast reply. My big squamosa died the next day. I had put another small one in before I sent you the letter and it did not last through the night. I suspected the spawning was the culprit and you confirmed it. I hate losing one of my animals, and they say an aquarium is a stress buster, HA! I go into stress mode if I even think something is going wrong. I'm doing water changes of 8 gallons a week. Should I do it more times than once a week?
Again, thank you. Sharon
As for water changes, I would recommend 15% once each week for the next four weeks. And if possible, vacuum the sandbed once during this timeframe, preferably right before a water change, as the new water can replace what was vacuumed out. I hope this helps get you back on the right track. Here's another clam book you should have; 'Giant Clams in the Sea and the Aquarium' by James Fatherree, ISBN 0-9786194-0-4.