What Type of Goldfish Can Go in the Same Aquarium?

Same breed

• There are two types of goldfish--common and fancy. A common goldfish has a long slender body, short dorsal fins, forked tail and orange-colored body. Often referred to as comets, common goldfish are the most popular pet fish, according to petgoldfish.net. Retailers often sell common goldfish as they are consider the best for aquarium beginners. Fancy goldfish look very unusual; they have round bodies, long glowing tails and bulging eyes. Examples of fancy goldfish species include moors, orandas, ranchus, bubble-eyed celestials and fantails.

Goldfish of the same swimming ability

• Common and fancy goldfish should not share the same aquarium. Common goldfish swim fast and gobble up food at a faster rate than slower-swimming fancy goldfish. According to goldfishtypes.net, because of their oddly shaped bodies, along with long dorsal fins and tails, fancy goldfish have trouble moving through the water. These fish tend to snake through the water as they bodies preclude them from darting quickly. Fantails for instances, struggle to swim as their long fins and tails limit their movements.

Same Size

• Common goldfish can grow to 2 feet long with an abundance supply of water and food. Some breeds of fancy fish can get just as big, but on average fancy goldfish range from 4 to 10 inches in size. Moors, for example, can reach 10 inches in length if placed in a large fish tank by themselves or with few other fish. The size differential between the two species of goldfish can have an effect if the two occupying the same aquarium. According to petdoc.com, common fish release large quantities of waste in the water. A common goldfish releases urine and feces a minimum five of times a day, according to petdoc.com. The levels of ammonia in an aquarium rise as large common goldfish secrete waste. Because of large quantities of waste excreted into the water by larger common fish, an aquarium can become toxic and lead to disease and death of goldfish. According to fishchannel.com, fancy goldfish are more sensitive to ammonia in water.

Water Temperature

• When it comes to water, the two types of goldfish enjoy different temperatures. Common goldfish prefer colder water below 75 degrees. Fancy goldfish prefer warm water temperatures ranging above 75 degrees. Placing the two types of goldfish into an aquarium is advantageous to one species in terms of temperature but would lead to the death of the other species. For instance, a fancy goldfish placed in aquarium where the temperature ranges below 65 degrees would become sluggish, unable to eat and eventually die, according to fishchannel.com.

Healthy Goldfish

• Only healthy goldfish should share the same aquarium. Placing fish exhibiting unusual behavior such as shaking, swimming on their sides and lack of appetite could end in the death of all aquarium goldfish. Furthermore, fish that have white spots (fish lice) and other diseases should never share the same tank, as disease could spread and kill the entire fish population in the aquarium.

  According to kokosgoldfish.com, fancy goldfish experience fish rot of the tail and dorsal fins at a much higher level than common goldfish. The reason is due to their unusually long fins. Lice and fungi attach to their long extremities more so than the short tail and fins of a common goldfish. Common fish experience diseases such as ich (a parasite that attaches to a goldfish), which is spread by unsanitary waste conditions; this frequently occurs in small aquariums with large common goldfish.