freshwater fish

Chapter 12 Tropical freshwater fish

Around 80–90% of tropical freshwater fish are captive bred, with typical hot spots of production being Singapore (e.g. Fig. 12.1), Malaysia, Israel, Florida and the Czech and Slovak Republics. Some important fish to the industry are still wild-caught however, such as the cardinal tetra (Paracheirodon axelrodi) from the Amazon basin.

For general information on fish consultations, examination, nursing care and anaesthesia, see Chapter 11, Goldfish and Koi.

Recommended water quality parameters for different aquariums are listed in Table 12.1. Water hardness is measured in a variety of different ways with mg CaCO3 as international standard. Conversion factors from other units are given in Table 12.2. Common species of tropical freshwater fish presented to the veterinarian are listed in Table 12.3.

Table 12.2 Water hardness conversion factors

Unit Conversion factor to (mg CaCO3)
dH 17.85
Clark 0.07
f (French) 0.1
Hardness 1
Milliequivalent (mEq) 0.02

Skin disorders

Structure and function of skin (see Ch. 11, Goldfish and Koi).

Differential diagnoses for skin disorders

Changes in pigmentation and colour

Treatment/specific therapy

Table 12.4 Recommended dose rate for benzalkonium chloride

Benzalkonium chloride concentration (mg/L) Duration of bath (min)
10 5–10
5 30
2 60
1 Several hours

Table 12.5 Recommended chloramine-T concentrations for different pH and water hardness combinations

pH Concentration in soft water (mg/L) Concentration in hard water (mg/L)
6.0 2.5 7.0
6.5 5.0 10.0
7.0 10.0 15.0
7.5 18.0 18.0
8.0 20.0 20.0

Respiratory tract disorders

Note that many freshwater fish can utilize atmospheric air. Lungfish (Protopterus spp) anabantids (including the popular gouramies (Trichogaster spp), fighting fish (Betta spp) and paradisefish (Macropodus spp)) and some South American catfish such as Hypostomus punctatus and corydoras are common examples. Gulping for air in these species may not necessarily indicate a respiratory problem.

Aug 21, 2016 | Posted by in EXOTIC, WILD, ZOO | Comments Off on freshwater fish

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