Neon tetra care in India: shoals, soft water and time away

The neon tetra, Paracheirodon innesi, is a wild species, a small South American characid. The US Geological Survey gives its native range as the upper Amazon basin of Peru, Colombia and Brazil. A 1999 study in Physiological and Biochemical Zoology describes its home waters as ion-poor and acidic, and found that neons kept their salt balance for two weeks at pH 4.0 and 3.5, though all died within hours at pH 3.25.

A 2021 study in Animals calls the neon tetra one of the most well-established and commercially important species in the aquarium hobby, and notes that breeding methods were worked out years ago. The fish sold today come from that long trade.

No source we found documents when neon tetras came to India or how many are bred here rather than imported. A national study of 27 ornamental species sold in aquarium markets in Delhi, Mumbai, Kolkata, Kochi and Chennai from 2019 to 2022 included other tetras, finding a gill fluke on black tetras, but did not list the neon tetra.

That study also notes that imported ornamental fish must be quarantined for 15 days and that releasing them into the wild is an offence. In Indian homes, the neon's needs are a heated, shaded tank and water that does not swing in temperature through summer and winter.

Neon tetras have small mouths, so feed a fine flake or micro pellet made for small tropical fish. The 2021 Animals study raised neons on commercial flakes and on freeze-dried natural food and found no difference in final body weight between the groups. The Merck Veterinary Manual says commercial dried foods are a good choice and warns that live foods can bring in parasites.

The RSPCA advises two or three small meals a day, only what is eaten in two to five minutes. Remove leftovers so they do not foul the water.

Meals a day: young neons, 2 to 3 tiny meals a day; adult, 2 to 3 small meals a day.

The RSPCA lists tetras among shoaling fish and advises groups of six or more, saying fish kept in smaller numbers may feel stressed and that a group comes out of hiding more readily. A 2021 study of neon tetras in Animals cites earlier work that found larger groups had a calming effect on neon tetras. RSPCA Australia says neons can share a betta's community tank of 40 litres or more if kept in a shoal of five or more.

For a sitter, the shoal is also the hardest thing to check. Neons move together and hide in plants, so counting takes patience. Ask the sitter to count twice, and leave the number on the tank. A neon that keeps apart from the group, hangs near the surface or swims oddly is the one to report.

The 2021 Animals study kept its neon tetras at 25 °C. In much of India that means a heater is needed in winter and shade in summer. A closed room in May can push a small tank well above the owner's range, and the Merck Veterinary Manual says warm water holds less oxygen. Keep the tank out of the sun, run an air stone, and leave a battery pump for power cuts.

Neons come from soft, acidic, mineral-poor water. Tap and borewell water vary a lot between Indian cities, so owners who prepare or soften water should leave enough prepared water for any change, and the sitter should never top up with untreated tap water.

Neons are small and peaceful, so the risk comes from their tank mates. RSPCA Australia warns that some tetras nip fins and names neons among fish that can live with a betta in a large enough tank. Merck notes that the same muscle parasite affects neon tetras and angelfish, so a mixed tank shares that risk.

Ask the shop which fish were in the neons' tank, buy from tanks with clear water and no dead fish, and quarantine new fish before adding them. Do not add fish just before a trip.