Hillstream Loach

• This loach is found in fast flowing streams at elevated altitudes. The hillstream loach can be housed in an unheated aquarium, which makes this species suitable for inclusion in a goldfish tank. Hillstream loaches require high oxygen levels when in the aquarium, so an aquarium with an aerator will be necessary. These fish will scavenge in the goldfish aquarium, but will require supplementary feeding once they have cleaned the glass, substrate and décor of algae and debris. These fish are accustomed to a fast moving current in nature, but will acclimatize to less current when housed in an aquarium, provided the oxygen levels are high.
  
  

Dojo or Weather Loach

• The weather loach is a slender, active fish that grows up to 6 inches in length. This species prefers to scavenge in a fine gravel substrate and often burrow into the gravel. Goldfish aquariums that contain these loaches require a canopy, as the weather loaches sometimes leap from the tank. These peaceful loaches are true cold water species and are therefore well suited to goldfish aquariums. The weather loach is a hardy species that is able to survive poor water conditions and low oxygen levels. This loach can swallow atmospheric air and extract oxygen as it passes the air through its stomach.
  
  

Corydoras Catfish

• The corydoras catfish is a peaceful scavenger. These small catfish are suitable for inclusion in goldfish aquariums, provided their diet is supplemented. Corydoras catfish are social and should be housed in small groups. It is important to feed these fish once they have exhausted the algae growth in the aquarium. Corydoras catfish will readily accept shrimp pellets and sinking algae wafers.
  
  

Hoplo Catfish

• This South America catfish is a peaceful scavenger that is hardy enough to be included in a goldfish aquarium. This catfish does not hide and can be enjoyed for its attractive appearance. Hoplo catfish will eagerly accept all the standard sinking aquarium foods, during times when the algae in the aquarium has been depleted. This species can grow up to 8 inches in length.