William H Wildgoose MRCVS
Pet fish vet
Mouth problems in goldfish
Goldfish develop various problems in and around their mouth. They commonly forage by sucking sand or gravel into their mouths in the search for food particles. Occasionally, large pieces of gravel get stuck, but in many cases, these are expelled unaided by the fish after several minutes. This is most common in goldfish living in indoor aquaria where they are more closely observed. Bacterial infection of the mouth is less common and often related to poor water quality. In contrast to koi, virus infections and tumours around the mouth are uncommon in goldfish.
Owners may seek professional assistance when gravel is stuck in the mouth, but often during the netting, bagging and transportation, it is dislodged and expelled before they reach the clinic. On rare occasions, it can get stuck because of its relative size and shape, and cannot be expelled by the fish.
Sedation is usually required to allow large pieces of gravel to be grasped and carefully removed with forceps to avoid damaging the delicate lining of the mouth. In this case, the gravel had been stuck for two days before it was pushed further into the mouth and rotated before removal.
Several bones form the complex shape of the mouth: the dentary (d) is similar to our jawbone, and the pre-maxilla (pmx), together with the maxilla (mx), forms the upper jaw. These bones move together to allow the mouth to extend and suck up food items as the fish searches through sediments. © Winfield, I.J. and Nelson, J.S. eds. (2012) Cyprinid fishes: systematics, biology and exploitation. Springer Science & Business Media.
Owners may seek professional assistance when gravel is stuck in the mouth, but often during the netting, bagging and transportation, it is dislodged and expelled before they reach the clinic. On rare occasions, it can get stuck because of its relative size and shape, and cannot be expelled by the fish.