Goldfish maximum mouth size?

[cgrabe]

What's the largest size item a typical full-grown fancy goldfish can fit in its mouth? I'm preparing my tank for a couple young-uns and would prefer that they don't choke on anything. My primary concern is substrate. I'd like to use those river pebbles they sell at walmart if I find them to be inert. Off the top of my head, I'd guess they're around half an inch across? If they end up being too small, my next choice is the larger river stones.

 

[aquariumfishguy]

Small gravel is a GOOD thing. The smaller the gravel is, the easier it is for your Goldfish to spit it back out. The problem with choking and the like is that they can't disgard the large rocks after they suck them up. This is why many of us recommend 1/4" rocks for goldfish setups.

 

[cgrabe]

I've heard that but would personally prefer something larger. I don't want to endanger the fish though, so I want to find out whereabout the upper limits are. They won't have trouble spitting it out or passing it if they can't get it in to start with.

 

[cgrabe]

Well based on some stray comments I've dug up around the web, the pebbles I prefer probably won't be an option once the goldfish start growing. I'll probably go with the larger stones. Thanks for your comments.

 

[aquariumfishguy]

A fully grown Goldfish has a very big (wide) mouth. They will always be found trying to suck up whatever is on the bottom of the tank. You'd be looking at getting very large river rocks for a goldfish, if you don't want him/her to bother with it.

 

[cgrabe]

The stones I have in mind now are probably in the range of 1.5-2" across. By the time the goldfish grow large enough to even consider picking up one of those, I'll probably have had to relocate the tank and will have the option of rethinking the substrate. I'll be buying the goldfish as young as I can so should have plenty of time to keep an eye on them before it's an issue.

 

[Cearbhaill]

I tried something similar to what you are describing at one point, but abandoned the idea once I saw how large Goldfish could move rocks. I became positive that the tank would eventually be cracked by them dropping stones.

I went for barebottomed. It is the cleanest, easiest thing to do and truly- I came to love the look of a spanking clean barebottomed tank.

 

[cgrabe]

Originally posted by Cearbhaill
I tried something similar to what you are describing at one point, but abandoned the idea once I saw how large Goldfish could move rocks. I became positive that the tank would eventually be cracked by them dropping stones.

Well the stones won't be directly on the glass bottom. On the bottom of the tank near the center will be the filter intake. A false floor (acrylic) will slope toward the intake from all directions. Raised slightly higher will be a plastic mesh upon which the stones will be resting. I think fine gravel would interfere with the flow of waste into the filter intake.

I hadn't thought about the impact of dropped stones. I can make some minor changes to allow the mesh to absorb shock pretty well. Thanks for your input.

 

[increment]

8 millimeters diameter , based on study of 1000 fairground prize size, as opposed to dinner size, done by the N A O M TS O G f M I D