Understand the Basic Parameters of a Marine Aquarium
In the previous article, How To Setup a Healthy Marine Aquarium for Your Marine Creatures, I gave a basic overview of the marine biological filtration system and the importance of the cycling process.
Only when the cycling period is completed around the 30th day, and you have tested that all the toxic components of salt water in a newly set-up tank have been processed to harmless levels, should you begin to stock up slowly with fish.
Difference Between Marine Fish and Freshwater Fish
Marine or saltwater fish are adapted to life in an ecosystem that is totally different from that of their freshwater cousins. The former are much more sensitive to changes in their environment.
Most of the marine fish for sale are commonly caught from the tropical seas of the Indo-Pacific regions. The water quality and parameters of salt water in your tank should thus closely resemble the natural seawater in such regions.
Basic Parameters of Marine Fish Tank
The critical parameters of a saltwater tank are pH, nitrate, salinity, and temperature.
pH Level: The pH of a marine tank is one of the most important features. All marine creatures like a pH near 8.2 ranging from 8.0 to 8.4. Marine fish and invertebrates are especially sensitive to rapid changes in pH levels, so keeping pH fluctuations within 0.2 each day is crucial.
Nitrate Level: The next critical parameter is the nitrate level. Saltwater fish are generally more tolerant of higher nitrates than invertebrates, but they still like nitrate levels below 20ppm with less than 5ppm being required for most invertebrates. A good goal would be to keep the nitrate level below 0.5ppm.
Salinity: The next parameter of concern is salinity, or specific gravity (the amount of salt in the water). Specific gravity is temperature-dependent, while salinity is not. Instruments that measure specific gravity are called hydrometers, and these will read the correct specific gravity at 59˚F. Most hobby-grade hydrometers, however, are temperature-corrected to read specific gravity at 77 deg F (25˚C).
Most creatures will acclimatize to almost any specific gravity, within reason, so long as it does not vary too widely. The specific gravity of a saltwater tank should be around 1.022. It’s worth noting that the salinity of natural seawater varies according to location (ocean, lagoons, estuaries), ranging anywhere from 1.020 to 1.030. Different fish may be native to different salinities, and may need some time to acclimatize to a different salinity.
Temperature: Finally, the temperature of a saltwater tank is basically the same as that of a freshwater tank. With a range between 75˚F and 80˚F (24˚C and 27˚C) with 77˚F (25˚C) being an ideal midpoint.
Compatibility and Feeding Requirements
The most recognizable of all marine fish are common clownfish, popularized by the movie “Finding Nemo.” Most casual hobbyists will not know much about them, or about the many thousands of different species of marine fish in the sea, unless time and effort are spent to gain more knowledge about them before making a purchase.
Compatibility: The clownfish, blue tang, Moorish idol, and porcupine fish on which the movie characters were based all have different feeding requirement, habits, levels of aggressiveness and may not be compatible with each other. Potential competition or fighting amongst tank mates could result in starvation, injury, and death!
Food: Marine fish may be herbivores, omnivores or predators. Some even feed on coral, sponges, and other invertebrates.
I highly recommend you buy good marine hobby books and google some reliable saltwater or marine aquarium websites. Doing so can help you learn more about fish species before buying them to save you money, frustration, and heartache.
