Question about Stunting and Adding New Fish

[Gillbert225]

I have a comet goldfish, who for his first year lived in a 10 gallon tank, which has stunted him to 4 inches in length. He now lives in a 55 gallon tank but hasn't grown any in six months.

My first question is will his organs be crushed from the inside because of stunted growth? It's never been fully explained to me whether the crushing is due to stunted growth in a small tank versus just stunted growth. If the crushing is from the former, then I would assume him being in the now 55 gallon tank will result in Gillbert living out a happy, non-organ crushing, life and can continue to question two.

As you can guess with a 55 gallon tank and a 4 inch long fish, my tank is rather desolate. Would it be safe to add a smaller breed goldfish (a fancy or black moor)? I've looked at aqadvisor (tank to fish calculator) and my filtration makes the tank compatible for one comet goldfish and one fancy/black moor goldfish (besides the big red message saying the comet will need a bigger tank as it grows).

Disclaimer: I would never add another fish if it meant endangering the life of my current one (Gillbert). This is entirely out of curiosity and a long-term idea, if I were to go through with it I would most likely wait a while before actually implementing it.

 

[Delapool]

Hi, welcome!

Is that 4inches including tail?

When I first started I had a tank about that size or smaller and a comet outgrew it. Very slow growth. Was maybe 3 or 4 inches.

The park had a goldfish lake system so I put him in that as was looking too big for my tank. About a year later a friend and I caught him and the body alone must of been a very solid foot. So must of been very good growth in larger water body. Possibly better food as well although not such an issue nowadays.

Have you looked at other small coldwater fish or did you want a fancy type goldfish?

 

[Gillbert225]

yes, including tail. He grew to this size this past August, when he was still in the ten gallon and I transferred him into the 55, he hasn't grown since then.

 

[Delapool]

I would guess the tank environment hasn't helped and great news you have the larger tank but sometimes they are just runts as well. I've seen a few threads like that and have had several fish that grew well below the size of other fish purchased or from breeding tanks at the time.


Also tank water chemistry is important - are you testing water eg nitrates and doing >30%, weekly water changes? This and a quality food will help.

 

[Gillbert225]

I have a cycled tank, ammonia and nitrite = 0, nitrate under 40 ppm. I change between 1/4-1/3 of my tank (not sure how many gallons that is, just took a ruler to the side of the tank and drew marks for 1/3 and 1/4 from where I keep my water level normally.

I had been bad about water changes for a little while (working consistently and school kept me from being home except to immediately go to sleep). But I generally do a water change once every week, and for the period where I didnt do weekly changes ammonia and nitrite remained at zero, nitrate at it's highest was at 80ppm which I then did a water change and brought it to 10ppm.

 

[Delapool]

How about some smaller cold water fish? Give you a bit of flexibility on stocking / less chance of overloading tank if busy. Found a link - would have to double-check in your area / suitable I guess.


https://en.wikipedia.org/wiki/Coldwater_fish