Boxfish has white lump on side

Kitana_S86 · Aug 8, 2025

My boxfish has developed a white lump on it's side in the last 5h. He doesn't look distressed as he keeps coming to see me everytime I get near the tank to take a picture. A couple of days ago I noticed this black shading on his belly as well, but don't know if it's related as he sometimes goes dark when he is spooked. Any input would be great.

vetteguy53081 · Aug 8, 2025

Kitana_S86 said:
My boxfish has developed a white lump on it's side in the last 5h. He doesn't look distressed as he keeps coming to see me everytime I get near the tank to take a picture. A couple of days ago I noticed this black shading on his belly as well, but don't know if it's related as he sometimes goes dark when he is spooked. Any input would be great.

This can be constipation or liver issue with fluid build up which I dont suspect at this time. I dont see injury infection, leading to blockage.
Is fish still eating?

Kitana_S86 · Aug 8, 2025

He is still trying to eat like a pig and apart from swimming a bit sideways, he is acting as normal.

Kitana_S86 · Aug 8, 2025

He's had a wound on the side of his mouth for a while from when he stuck his face in the slow feeder. I just took another picture as the lump seems to still be growing. You can see the mouth better too. I don't know if they are related since the wound was a while back and it looks like it just healed funny. What do you think?

vetteguy53081 · Aug 8, 2025

Kitana_S86 said:
He's had a wound on the side of his mouth for a while from when he stuck his face in the slow feeder. I just took another picture as the lump seems to still be growing. You can see the mouth better too. I don't know if they are related since the wound was a while back and it looks like it just healed funny. What do you think?

This is not constipation and I would isolate in a separate treatment tank adding Seachem Kanaplex which is absorbed by the fish and add an air stone while treating