Black Widow Tetra 3.5cm

Black Widow Tetra

The Black Widow Tetra is an extremely under-rated schooling fish for aquariums. They are often overlooked because of the monotone colouration but their simplicity and unique body shape along with their phenomenal schooling behaviour is something which is only truly appreciated when kept. Black widow tetras have a characteristic coin like body shape which makes them look similar to the larger growing silver dollar species of pacu.

Whilst the latter fish may get far too big for most aquarists the black widow tetra stays at a maximum size of 6cm which makes them great for smaller aquariums. They also have a simple but great array of silvers and the jet black colour they sport as stripes and the nape of their body which leads to their fins. Their large ventral fin also earns them the name black skirt tetra as it almost looks like a small dress they are wearing.

Black Widows are also extremely versatile in the temperature range they can be in and can be kept in temperatures from 24-18 degrees. Because of their community aquarium tolerance, they are also evidently extremely peaceful fish but feel best when kept in schools of 6 as a minimum but ideally, 10 or more would be perfect. breeding these fish in captivity is somewhat easy where females tend to be more rounder bellied than males. Females will scatter eggs through the aquarium and males follow by fertilising. The wild origin of cardinal tetras is South America.

Tank Recommendations for your cardinal tetra

Being a small and relatively easy to care for fish the cardinal tetra can be kept in nano aquariums with the minimum being 20 gallons (75 litres). This aquarium size allows for a decent school of these tetras along with other community fish if required. A sand or gravel substrate would be fine for these fish as well as a lot of plant growth which not only makes them contrast really well but also makes them more comfortable in the aquarium. Black Widow tetras are soft water fish meaning they require a low PH. They can be kept in PH as low as 6 and will even look stunning in a blackwater aquarium setting.

Suitable Tank Buddies

The black widow is an extremely peaceful fish that displays no aggression, they can be kept with a wide range of fish being top, bottom and mid dweller fish. 

Usually Compatible

Discus, Angelfish, glowlight tetras, neon tetras, Apistogramma, rams and a range of dwarf/nano peaceful fish.  

Sometimes Compatible

Cardinal tetras can be a relatively slow fish so any fin nipping species of fish that may outcompete them for food such as guppies, tiger barbs or Roseline sharks

Rarely Compatible

Large and aggressive species such as rainbow sharks, Raphael catfish, larger mouthed community fish may prey on the tetras and large cichlids.

Feeding your Black Widow tetra

Black Widow tetras are a very easy fish to feed. They will take a wide range of pellets, flakes and frozen foods. Just like any fish though they should be fed a varied diet with a mix of different foods. The ideal diet would be a good quality micro slow sinking pellet or crushed flake, supplemented with frozen bloodworms or black worms or even live foods like baby brine shrimp or micro worms.