L144 Bruise or something sinister?

Shimmer

New Member
Jun 27, 2015
3
0
1
Ohio
Larry started out with a small dark spot on his back after a driftwood accident months ago. I figured it was a bruise but it keeps getting bigger and darker. He acts and eats normal (algae wafers, cucumber, zucchini), and he isn't itchy.

He's in a 29 gallon planted tank, pH 7.0, Ammonia 0, Nitrites 0, Nitrates 40. I do 30% water changes once a week, sometimes twice since the nitrates are up. Temp 80 degrees Fahrenheit.

Tankmates are 3 other BN plecos, 2 cories and a bunch of guppies. MTS, rams and bladder snails (trying to get rid of the rams and bladder snails).

Here's a pic, what do you think it is? My albinos never had spots.
 

Attachments