The Living Aquarium's Indicator Fish of choice is the Rummy Nose Tetra. They thrive in the same conditions as our Discus and help us by giving early warning if our water quality is bad. If Ammonia or Nitrate levels begin to rise, the bright red begins to fade and we instantly know something is wrong. We have 8 or 10 in the tank and they eat the same blood worms as the Discus, so no extra attention is need for them.
The rummy-nose tetra, Hemigrammus rhodostomus, is a species of tropical freshwater characin fish originating from South America and is a long established favourite among tropical fishkeepers. The fish is one of several very similar species including Hemigrammus bleheri and Petitella georgiae. It is possible that more recently collected specimens available in the aquarium trade are members of one or other of these alternative species. The common name applied to most of these fishes is "rummy-nose tetra", though other common names are in circulation such as "firehead tetra"
The details of aquarium maintenance for all three species are more or less identical: the rummy-nose tetra is a schooling fish, which exhibits tight schooling behaviour both in the wild and in the aquarium. Consequently, these fishes should be maintained in groups of no fewer than six individuals, with larger numbers being preferable where space permits
The water chemistry preferred by these fishes, as might be inferred readily from that of the wild habitat, is soft, acidic water (hardness no higher than 6° dH and pH around 6.4-7.0 is definitely preferred if possible) though for maintenance purposes, the pH of the aquarium water can range from 5.6 to 7.4. However, if captive reproduction is to be attempted, the rummy-nose tetra needs soft, acidic water, as Tropical Fish Hobbyist magazine recently reported that research work upon these fishes indicates that high levels of calcium ions in the water induce sterility in these fishes. A planted aquarium is welcomed by these fishes, particularly if the plants include fine-leaved species such as Cabomba and Myriophyllum.
Feeding presents relatively few problems, as the fishes will eagerly devour a range of prepared as well as live fish foods. In common with numerous other tetras, these fishes are particularly fond of live bloodworms (these are the aquatic larvae of a midge belonging to the genus Chironomus) and will also devour live Daphnia avidly. Unlike those tetra species which adapt to surface feeding in the aquarium, rummy-nose tetras are not considered likely to add live mosquito larvae to their diet in the aquarium, though instances where these fishes discover and enjoy this food are possible: usually, rummy-nose tetras prefer to take their foods in the middle and lower regions of the aquarium.
Lifespan for the rummy-nose tetra in the aquarium is usually 5 to 6 years with careful maintenance. Exceptional specimens can live for more than 8 years.
The fish is interesting in that it can act as a "mine canary" in an aquarium, alerting the aquarist to potential pollution problems in an aquarium. When levels of certain metabolic wastes (ammonia, nitrites and nitrates) exceed critical levels, the intense ruby-red colour of the fish's facial area becomes pale. The fishes also become pale in appearance immediately after the disturbance that takes place in the aquarium following a water change, but in this instance, once clean water has been supplied, the intense deep red colour returns. Persistent paleness of the head is to be taken as a sign that water chemistry parameters in the maintenance aquarium are in need of adjustment, and that pollutant levels are becoming dangerous for the inhabitants.
From Wikipedia, the free encyclopedia
http://www.en.wikipedia.org/wiki/Discus_(fish
