Edges of Goldfish Tail Turning Black...

[sara.thom0710]

Just noticed my goldfish's tail is turning black on the edges. I just set up the 10-gallon tank about 2 weeks ago and have about 9 fish in it. The goldfish is the only one with black on its tail. There are two other goldfish in there that are fine. I don't have a water testing kit but I heard it could be ammonia burns? What else could it be? Is it normal for goldfish to get black edges on their tail?

I have attached a picture of the fish.

 

[Delapool]

Just noticed my goldfish's tail is turning black on the edges. I just set up the 10-gallon tank about 2 weeks ago and have about 9 fish in it. The goldfish is the only one with black on its tail. There are two other goldfish in there that are fine. I don't have a water testing kit but I heard it could be ammonia burns? What else could it be? Is it normal for goldfish to get black edges on their tail?

I have attached a picture of the fish.

Hi, welcome to the forum and congrats on your new fish.

Unfortunately I have some bad news - some of which you have hit on the head.

A recent colour change like that suggests some sort of chemical burn, of which ammonia is very possible.

I would grab a water test kit (eg API freshwater master test kit) or get the store to test for ammonia and ph. I've also included some links below on cycling a tank to establish good bacteria. Assuming your tap water is ok, I would do a 30% water change (temperature match and add your water conditioner).

The very bad news is that the size tank you have is not suitable for any goldfish. Unfortunately the fish will produce more waste then every daily water changes can handle (however daily, 30% water changes are likely needed until you can rehome them). The second link is useful for stocking guidelines. For example I have a single betta in a 5 gallon tank.

http://www.aquariumadvice.com/forum...ou-get-started-with-your-aquarium-154837.html

AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor

 

[sara.thom0710]

Thanks, so if a 10 gallon tank is the wrong size for goldfish, how do people get away with having them in a small bowl? just curious, i'm new to this.

 

[Delapool]

Thanks, so if a 10 gallon tank is the wrong size for goldfish, how do people get away with having them in a small bowl? just curious, i'm new to this.

Hi, good question. Common goldfish like comets are really a pond fish or need a large tank. A friend of mine has a fancy goldfish in a three or four foot tank - the goldfish would be about 7 or 9 inches excluding tail.

Goldfish are extremely hardy fish which means they can survive in cramped bowls with poor water conditions. Unfortunately this stunts their growth, weakens the fish and viral/bacterial infections commence. Scale colour is not as vibrant and ammonia burns are possible.

Generally the world has moved on from goldfish from the fair in a bowl. I'm not aware of any forums suggesting it is a reasonable idea however marketing on some small tanks catches people out. Unfortunately over the years I've seen a few similar threads. Either rehoming the fish or going to a much bigger tank are the better options.

When I started out I had several goldfish in a 30 or 40 gallon tank. Eventually a comet got too big and we put it in a goldfish pond / well. About 6 to 12 months later the darn thing was over a foot long and just a solid fish.

 

[nirbhao]

Thanks, so if a 10 gallon tank is the wrong size for goldfish, how do people get away with having them in a small bowl? just curious, i'm new to this.

The fish don't live long. Goldfish can live for decades in good conditions. In a bowl, they'll survive a year or two.

I didn't know better in the beginning. It's a learning curve. I now use my one gallon bowl to sex guppy fry and getting plants to drop new roots.

 

[Floop123]

It could be fin rit