Ranchu with hole in tail

[Florencep]

I’ve had this ranchu for six months, he is in an 80L tank with one other fish (oranda). Did proper quarantine procedure and he’s never been poorly before.

I’m very meticulous with water condition (hoover out poos daily, weekly 1/3 water changes). Water tested this morning with my test tube kit and the PH/nitrates/ammonia levels were all perfect.

The ranchu suddenly has a hole in his tail (see picture). It looks a bit like ammonia burn but can’t be. We’ve ordered specific fin rot medication (I regularly dose with Interpet general disease treatment anyway as a preventative) - but can it really be fin rot? I thought that started at the tips. Seems odd to start right in the middle of the tail like that.

I had noticed in the past that his tail joins very closely together at the back, almost like it could be two bits of tail rubbing together. Or something stuck in there?

I did a 75% water change this afternoon and will do another big water change when the fin rot meds arrive, to clear out the general Interpet disease treatment as I know the two meds aren’t for concurrent use.

Any opinions and advice much appreciated.

 

[Aiken Drum]

Please take a read through the "unhealthy fish" sticky and give as much detail as you are able.

https://www.aquariumadvice.com/forums/f17/before-posting-about-unhealthy-fish-read-this-32451.html

Saying things are perfect doesnt help as we have no idea what you consider perfect.

In addition could you tell us how big your fish is?

On the face of it, an 80 litre tank is too small for 2 goldfish and this could be causing health issues.

 

[Florencep]

Thanks for your reply.

PH - 8
Ammonia - 0
Nitrate - 0

Both fish are small, both probably less than 2 inch bodies. I’ll be upgrading to a bigger tank when we move shortly, but for now overcompensating with regular big water changes and poo sucking. Thanks.

 

[Florencep]

Substrate is white sand, theres one large java fern on a log which I prune (remove leaves from) weekly to keep the growth down. No new ornaments in last 6 months.

 

[Aiken Drum]

Are those the water parameters before or after your 75% water change?

Not seeing nitrate is a sign you arent cycled or there is something amiss with your testing. "Perfect" water parameters would be 0 ammonia + nitrite and some nitrate. You havent mentioned nitrite in your testing. You mention 6 months. Is that how long the tank has been set up? If so, it should have cycled by now. If its cycled and you are seeing zero nitrate then there is something wrong with your testing. 2 goldfish in an 80 litre tank will be producing measurable nitrate in a cycled tank with the water change schedule you are reporting.

A 6 month old goldfish should be bigger than 2". So it is already stunted, which causes other health issues.

I wouldnt consider a weekly 1/3 water change as being "regular big water changes" for 2 goldfish in a too small a tank. Fish release hormones when they are living in a poor environment to prevent them outgrowing their environment. Their bodies stop growing, but their internal organs don't. This causes ill health and poor immune response. Big, daily water changes might be enough to remove these hormones, but weekly changes wont.

Yes, it looks like fin rot to me. You can treat the fin rot, but the cause will still be there.

I would double check you are testing correctly and try and test for nitrite also. What test kit are you using. What fin rot medication have you ordered?

 

[Florencep]

Sorry to be clear, the tank has been set up for years and is cycled.

Honestly I don’t write parameters down anymore, I just look at the colour by eye against the colour charts. The Na is not zero but its a light acceptable colour on the colour chart.

The fish were very very small when I bought them (intentionally as I don’t have a big set up). The oranda has easily doubled in size since we’ve had him. No stunted growth here.

Weekly water changes are a third to a half weekly, and any bit of poo is immediately sucked out the tank. I have pristine white sand and I know we don’t have a water quality problem.

Thanks for confirming it is fin rot. Hopefully the medicine can stop it in his tracks.

 

[Aiken Drum]

How long have you had the fish?