Freshwater fish found all over the world vary in their habitat needs and swimming level. There are variations in their temperament and lighting needs as well. Such information helps in selecting the right mix of freshwater fish and providing the required environment, specially for hobbyists. Not all of them are recommended for beginners. Some of them are strictly recommended only for experienced fish keepers, so as to maintain the required factors needed for their survival.
Chinese Algae Eaters
As the name suggests, these fish keep aquariums free of algae. Like most other fish, they prefer hiding places in wood, rocks, and plants. As they feed mostly on algae, a bit of sunlight on the aquarium is preferable for them. Occasional lettuce and spinach are also enjoyed by Chinese algae eaters. It is said that, if these types of freshwater fish are not provided with other food sources (not just algae), they tend to prey on other fish neighboring them.
Salmons are known to be very particular regarding their territorial rights. They do not prefer the company of other fish in their area of water. They are known as anadromous fish, which means that they live in the sea but reproduce in freshwater (stream or lake). An amazing fact about the life cycle of salmons is that they live in freshwater in their early life, get matured in saltwater, and return to breed in freshwater, before they die.
Black Ruby Barb
These freshwater tropical fish are usually found in streams on hills (300m from sea level). The black ruby fish is known to bear an aggressive temperament and prefers plants and rocks in their habitat.
Trouts and Sea Trouts
Having a torpedo-shaped mouth or which looks more like a pike, trouts generally stay in river. They get their name as 'Sea Trouts' due to the fact that some of them (mainly females) spend a part of their lives at sea (for about a year). After they return from their sea life, they tend to be larger in size than their 'like-ones', who did not go for a 'vacation at the sea!'
Goldfish are beautiful, ornamental freshwater fish. A common belief remains that they were among the first breeds of freshwater fish to be domesticated by humans. These species enjoy cool streams, lakes, and ponds. They neither have stomachs nor close their eyes while sleeping. Some exotic types of goldfish species include oranda, ranchu, and pearlscape. Goldfish types that can be commonly found are fantail, black moor, common goldfish, and veiltail.
Swordtails have the reputation of being peaceful in normal environment, however they are also known to be aggressive towards other males. They are also known to make great pets for freshwater aquariums. Swordtails fries must be kept away from other swordtails, as it is a common habit for these fish to eat the young ones. Prepared foods or live foods; both are their delicacies.
These freshwater fish fall among the schooling groups of fish. When kept in a fish tank, these fish form a group of six or more, and tend to produce a beautiful glow under proper exposure to light. Other types of these species are cardinal tetra, glowlight tetra, and black neon tetra.
These freshwater fish have enormous head size of 10 - 20 cm and thinly-shaped bodies, with large pectoral fins. They got their name 'bullheads' from their wide flattened heads. They keep their entire life span limited to one stretch of river and can be regarded as 'residential freshwater fish'. They prefer shallow water and living under stones, as they do not possess good swimming qualities. They feed mainly on invertebrates. Male bullheads become black and females become plump when they start the spawning period of their lives.
Minnows can grow to as long as 9 cm and are among the smaller freshwater fish in the world. They have prominent large eyes, small mouth, and blunt nose. They can be found in colors ranging from silver and gray to brown and yellow. They form an important part of trout diet and mostly dwell in the upper reaches of rivers. In case of these species, the back becomes black, the sides turn golden, and the belly and lower fins appear bright red during their spawning season.
Carps are the common and major species of freshwater fish found almost all over the world. They thrive in ponds and have a large family of fish like the common or king carp, mirror carp, koi carp, carp bream, bighead carp, carnatic carp, and crucian carp. Carp fish are associated with bringing good fortune to people in the Asian countries.
About 41% of the total known species of fish are freshwater fish, and they spend their lives mostly in rivers, lakes, ponds, streams, etc., with a salinity as low as 0.05%. As mentioned, different species of these fish have different needs and requirements with respect to their habitat and survival. This fact becomes important when it comes to keeping them as pets by beginners or professionals.