Goldfish tail bleeding (?) with possible fin rot

[EmilyS]

This is posted on behalf of my mother. I moved out 4 years ago but I am still caretaker of her fish. I haven't seen the fish in person, but I have some pictures.

10 days ago (Tuesday) my mother sent me this picture of my oldest goldfish:

He clearly had torn his tail on something (even though the only thing in the tank is the filter intake and a pretty flexible plastic plant). I'd seen their tails get a little red in the past after getting torn, so I wasn't too worried.

On Monday I ask for an update and get these pictures:

The red spot is still there and darker, and he's lost a significant part of the end of his tail. All the edges look a bit white, though it's hard to tell if that's the lighting or fin rot. I instruct my mom to dose the tank with aquarium salt (1 tsp/gallon), which she does over the course of the day on Tuesday.

Today (Wednesday) I ask for another picture:

It's the middle of the day so it's not unusual to see them resting on the bottom, plus they probably don't like the salt, so that doesn't really concern me. The red spot looks much less dark, but it is certainly eating away at the end of his tail.

Has anyone seen this on goldfish or other fish before? Is it an infection? Is the salt sufficient to get rid of it? My mom is leaving tonight and not coming back until Sunday night. Is there anything I should ask her to do before she leaves?

Ammonia is 0ppm. That's the only water parameter my mom tested. My mom hasn't mentioned problems with any of the other fish, but then again she didn't notice when the whole tank had mild fin rot a few months ago. I have also never noticed them nipping at each other's fins, though that doesn't mean they aren't doing it now.

FYI: the bottom part of his tail is short because six months ago I had to get him out of the tank in a hurry, used too small a net, and tore a piece of his tail off. I felt so guilty...

 

[Colin_T]

The white stuff on the fins is excess mucous produced by the fish to help cover and protect the damaged tissue. Fish naturally have a thin layer of clear mucous over their body to act as a first line of defense against microscopic organisms and poor water quality. If they are injured or stressed, they produce more mucous and it appears as a cream or white film over the body and fins.

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Goldfish can tolerate up to 4 heaped tablespoons of salt per 20 litres of tank water. I would do a 75% water change, gravel clean the substrate, clean the filter if it hasn't been done in the last 2 weeks, then add more salt. Use at least 2 heaped tablespoons per 20 litres and maybe go up to 3 or 4 heaped tablespoons per 20 litres.

Normally I say start with 2 heaped tablespoons of salt per 20 litres and if there's no improvement after a couple of days, then double the dose rate to 4 heaped tablespoons per 20 litres. Because your mum is going away for a few days, I would up the dose before she goes.

Keep the salt in the tank for at least 2 weeks but no longer than 4 weeks.
If there's no improvement after a few days with maximum dose rate of salt, then you might need an broad spectrum fish medication that treats, fungus and bacteria.

 

[EmilyS]

Excess mucous makes a lot of sense. I didn't know that! I'll keep it in mind if they ever get hurt again.
Thanks for the suggestion with the salt. For non-metric people like me: 1 tsp per gallon is about 1.6 tbsp per 20 litres. Even though that's less than what you suggested, it does seem to be helping.

The redness is almost gone and it seems to be healing well. I don't know if the red was the infection or if it was just indicative of one, but I'm glad the salt is clearing it up.

 

[Colin_T]

the red was a big clump of blood from where the tail fin was ripped off. The fins have veins in them and if they get damaged, they bleed. That's where the red was from.