I just got some 1" maximas and there seems to be some spiral tube growth on the shells. Maybe some type of worm, 1mm thick tube. Should I just clean everything off the clams? Thanks
Unless it's a detrimental parasite, leave it be. If the clam doesn't mind, neither should you. Worms tend to not be a problem if they are calcerous and build their own home. Only worry if it is a boring worm and drilling its way into your clam, then scrape it off. From the description, sounds harmless.
Look for small tiny white snails around the mantel and their clear jelly with white spots eggs. These snails do harm the mantel and weaken the calm to death.
Don't clean it unless something is causing it to seriously retract over a period of time. FWIW, I lost a Maxima that I'd had for a long time because I tried to remove a worm that was irritating the mantle. My big clumsy hands knocked the clam off his perch and for some reason after that he refused to reattach and eventually died.
Dan