gsp with dark belly only during the day?

[blue27343]

I have one GSP in a 30 gallon tank with an eheim canister filter listed for a 65 gallon tank plus a hang on back filter listed for 30 gallons and I run two air pumps with 3 airstones. I also have plenty of decorations, including fake mangrove roots, plastic plants, and a dark sand. The tank is fully cycled and has zero ammonia and nitrite. My puffer is fed twice a day from a selection of various foods (blood worms, mysis and brine shrimp, shrimp pieces and snails) and readily eats anything i give him. My only problems are he has a darker underside which always turns to a bright white at night, and two tiny specks of white on his right pectoral fin that are each about the size of a grain of sand. Any help would be appreciated.
Thanks,
-Matt

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[Boxermom]

Is the water freshwater or brackish?

[blue27343]

low end brackish

[Puffalicious]

Is he the same way when the lights are turned on? because on the picture it seems like the aquarium lights are off and he might be in sleep mode. I've notice that 10 minutes after I turn the lights off my GSP's belly turn dark and after a while he'll go to sleep. Also in the morning before I turn the lights on, his belly is also dark.

[Boxermom]

What's the SG at? How long have you had him? Is there anything else in the tank with him?

[blue27343]

The SG is at about 1.004 (what the store had him at when i got him) and he is the only fish in the tank. i've had him since june (at least 2 months) and no, the picture is during the day with the lights on, the camera just makes it look dimmer than it really is. every day he gets dark when the lights switch on and at night he turns back to a happy looking white color within an hour of lights out....

[spoot]

are you using marine salt or aquarium salt? Our ceylons will change back and forth during the day from dark to light. If your water is ok and there are enough decorations/hiding places, not sure what else you can do.

Does his belly get very sunken in? If so it may be a sign of internal parasites.

[blue27343]

I am using instant ocean, and I am not sure if his belly is sunken in, he usually looks pretty skinny before i feed him, could this be a sign of internal parasites? (I feed him twice a day, and after feeding he is usually a little fat looking) if so, what should I try treating him with? is there any meds for parasites that are a safe bet even if he doesn't have anything?

thanks....
-Matt

[manutius]

Could be IP, Flubenol is a great product if you can get it. Where do you live?

[blue27343]

North Carolina