Culling for crooked mouths........

[harzan]

I was noticing .... I have a young fish with a crooked mouth. I have not seen one all season. I did use a net recently to move and thin out the tanks. Do you guys think this cause is more of an injury or genetics? I use a lot less of nets this year and only noticed this one.

[Daryl]

It is possible that you injured the fry when using a net to move it, but I strongly suspect that what you are seeing is genetic. Some lines of fish carry common "flaws" - with some it is rudimentary dorsals, some show curled gills and some have mouth flaws.

If you have been seeing this type of genetic aberation from this line of fish in the past, then it is almost a given that this is genetic.

Unless these are REALLY rare fish - or you are struggling to keep a line going, I would cull this one - whether or not it was mechanically damaged or genetically induced.

[Virginia ranchu]

I highly doubt that a crooked mouth is related to netting. I have seen crooked mouths and curled gills from time to time, but it seems to be environmental. I am sure that overcrowding, poor water quality and poor nutrition can cause problems. You can test this theory by picking a few fry from a spawn and raising them separately at very low density, like 1 gallon per fish, then compare their growth to that of the rest of the spawn.

I also think that some spawns are more susceptible to problems. There are subtle things that can have a big effect. I think the condition of the female when she spawns has an effect on the size of the eggs and fry. I also think that oxygen levels, ammonia levels, and even temperature changes can affect developing eggs. Too much inbreeding can also produce weak or deformed fry. Are your fry from full sibling parents or parent offspring crosses?

Cheers,

Rob

[Cincy Ranchu]

This is a classic sign of inbreeding in Bristols and Veiltails. They have to be pitched and look for an outcross, you are on your way down a slippry slope.

[harzan]

I do not think thisw was inbreeding as this was an outcross.

What about bubbles under the mouth?

[Virginia ranchu]

Bubbles under the mouth is genetic. In fact, there was an article in the Goldfish Report a few years back about a new breed that had well-developed bubbles under the chin. I have never seen this in any of my fry, so I think it must be something genetic in your fish. What type of fish are you raising?

Rob

[harzan]

blue ranchu...about 2 have this out of about 300 that made it through 3rd culling.

I think tey were too small to notice before.

[sc569]

I have bred fish with mouth deformities. It is probably an inherited trait. I would never use such a fish as a breeder though. If it is just for looking, there is no harm in keeping it if you have the room. But, that fish will take up space, eat food and excrete by-products that will inhibit the growth of your other fish.

I would suggest that you choose breeders that are perfect in every way. Otherwise, you never know if the visible defect will be transmitted or not.

It is hard enough with fish that have no visible defects to raise good quality progeny.

[Daryl]

Boy, the day I get a fish that is perfect in every way, I am retiring!!!

Obvious flaws such as curled gills, bubbles under the mouth, etc. do need to be culled. But often fish with minor flaws can be good in a breeding program if they bring other genetic traits to the line.