T Derasa health question

[linuxpng]

I have a T Derasa clam (the only in the tank) that I've had for about 8 months. It's approx 8 inches long and 5 inches tall. In the last week he opens fully, but doesn't extend his mantle much (if at all). I don't really see anything picking at him (even underneath) but am a little concerned.

My water perameters are 1.025 for salinity, 400 CA 10 ALK 0 Nitrate 0 Nitrite and 0 Ammonia. I have other corals in the tank that are doing well.

My lights were replaced about 3 months ago and the clam was fine after that change as well. The clam is still very reactive to light changes (almost closes at night).

Is this something to be concerned about?

 

[Anonymous]

Not one area pinched in, just isn't opening fully, correct?

No recent additions of livestock, live rock? No change in any supplements or saltmix? Do you do any feeding?

My knowledge is limited. Just tried to ask questions that might help someone else provide a good answer. And maybe we both will learn something.

 

[Robin Goodfellow]

hi.
When T. derasa gets that large, it will start to slow down growth. But it should at least grow a bit in past 8 months. So did it? If it does, then a few day without fully extending its mantle is nothing to be concern about.

Check to see if you can find rice snail (looks like rice, and similar in size) near the mantle and the byssal opening. Typically T. derasa are pretty good in against these parasites because the byssal opening is very small, particularly for matured specimen like yours.

 

[linuxpng]

I've changed 2 things, I've stopped adding kalkwasser to my top off water a few weeks back and have added a small powerhead to circulate water in the back of my live rock better. I'm using b-ionic to get my calcium raised now.

The power head doesn't directly affect the clam, although it is possible that it has changed up current enough to bother it.

I haven't noticed anything on or around the mantle, but when I get home (at work unfortunately) I will check it out.