how "OPEN" should my clams be?

[Dooly]

I'm fairly new to clams and recently added a 2.5'' crocea and a 4'' gold maxima, they both are stuck on a slab rock next to each other and seem pretty happy there.

Now my question is.. how wide should they be open? I see pictures on this forum and some look like they are almost closed all the way and some are gaping wide open as wide as possible.. I will post pictures later, but I'd say mine are open about 1/2'' in the center most of the times .. i'll post some pictures later..

temp is 82-83
salinity 1.025
0 ammonia
0 nitrite
less than 5ppm nitrate

and under 8 54watt high output T5's 48'' in my 120g about 20 inches down

 

[Haddonisreef]

I like to tell by how much of the mantel is sticking out over the shell! Your temp is a bit high for me but if not going over 83 you should be good.

 

[diescreaming]

if you think they are closed up, do you have any angels, they will pick at clams

 

[Dooly]

no fish that nip on clams, i have a purple tang, tomini tang, couple wrasse, true percs, etc..

temp is set at 82.4 on my chiller, however fluctuates between 81.4-83.4 daily.. my clams seem like they are doing better though..

 

[Amphiprion]

Unfortunately, every clam is different in this regard, IME. Some individuals open more than others, but in general (IME), T. crocea and T. derasa tend to open up the most. T. maxima, squamosa, and gigas seem to be pretty variable overall. Hippoppus can open fairly wide, but have no mantle extension.