Hello - I've had a derasa clam in may tank for ~5 months. It has done well and grown significantly. I have 2 150W 10000K MH and 2 96W actinic lighting. Due to algae growth I have significantly cut back on adding liquid food supplements for my clam and corals in the last 2 months. I don't know if it is coincidence or not, but the clam began shifting back and forth in the sand at least one a day about a monht ago. Water parameters are good - no detectable amonia, nitrate, or nitrite. I've heard people use the phrase gaping and I beleive my clam has been doing that more in the last couple of weeks. It continues to look healthy with good color. Are any of these symptoms a warning flag?