Green Spotted Puffer Not Eating
It's been 7 days since he ate, 2 days ago we got the Nitrate down to 20, all other water chemical/temp (even 78) issues are not a concern (verified by multiple sources).
GSP is 4 yrs old, about 5 inches long and has always been a good eater. No sign of exterior parasites. Simply refuses all offers of food, even when held and placed in his mouth.
His teeth are healthy and his color stays between dark and somewhat lighter. Swims back and forth on bottom back side of 40 gal tank. Water is brackish at 1.015. No changes to tank for many months (other than maintenance), no new plants or objects added.
Only feed him clams, blood worms and sometimes squid.
What other reasons would he continue to NOT EAT?
Any suggestions would be appreciated.