Aquarium fish: Dichotomyctere ocellatus (Tetraodon biocellatus)
Size: 8 cm
Water temperature: 22-26 ° C
Aquarium volume: 70 l
Dichotomyctere ocellatus (Tetraodon biocellatus ) – small, interestingly colored aquarium fish from the puffer family.
Southeast Asia . The species is found in the areas of Malaysia, Cambodia, Borneo and Indonesia. It lives in the coastal calm waters of streams, river mouths and flooded mangrove forests.
It most often inhabits freshwater, but is also often found in brackish waters.
Characteristics and disposition
Reaches up to 8 cm in length. The body is short, oval and stocky, with a large head and slightly bulging eyes. Interestingly, the eyes move independently of each other. Underbelly white or cream.
The upper body is greenish-brown, decorated with various green-yellow patterns (dots, circles, stripes, spots) and a few larger black, yellow-edged spots. Usually, two large spots on the back resemble a figure eight, hence their colloquial name, Figure 8 Puffer . The pattern becomes more and more complex with age. The dorsal and anal fins are rounded and symmetrically placed in relation to the body. They do not have belly fins.
The lack of gill covers and scales makes them more sensitive to any contamination. The mouth of puffers is equipped with two pairs of strong tooth plates that allow them to crush and split the hard shells of snails or mussels. They have the ability to “get puffed up”. In an emergency, a specially adapted and very stretchy diverticulum of the intestine can fill the body with water or air. In addition, their tissue produces highly toxic substances.
They can also play dead by swimming upside down. External features do not distinguish between sexes . During breeding, females are usually slightly thicker (full of eggs). Despite their poorly developed fins, they are very active. They like a variety of surroundings and are eager to search every corner of it.
In the wild, they are found singly or in small groups. They tend to gnaw the fins of free-swimming and veiled fish . Males are not friendly towards each other, but in a sufficiently large tank they usually end up chasing their rivals away. In the aquarium it is recommended to keep individually or in groups of min. 4 individuals.
Nutrition and feeding
Omnivorous and predatory fish. In natural habitats, invertebrates, crustaceans and molluscs constitute a large part of their diet. In the aquarium, they can be given dry, frozen and live food, e.g. krill, shrimps, crab legs, snails, bloodworm, artemia, and adults also include scallops, clams, oysters, crayfish and crabs. From time to time, it is worth supplementing their menu with plant foods, e.g.
lettuce, spinach, zucchini. Pufferfish teeth are constantly growing and need to be naturally abraded. It is necessary to regularly feed snails in their shells. If neglected, they will stop eating at all.
For one specimen, approximately 70 liters of aquarium is recommended, partly densely planted with durable plants (the more delicate ones can be eaten).
For decoration, twisted, dry twigs or roots can be used to give them extra shelter. River sand will be the best substrate. The light should not be too bright, possibly muffled by floating vegetation. Despite the fact that they also live in fresh water, according to numerous opinions, they feel better and live longer in slightly salty water – brachic (approx. 1.005 – 1.008 SG).
They are fish that are very sensitive to pollution . They require efficient filtration and regular weekly water changes (30-50%). In bad conditions they lose their color and are not very active – they lie on the bottom or swim rolled up into a ball. They can be kept in a social aquarium, but mates should be chosen carefully. They belong to the fin-gnawing fish and are therefore not suitable for companionship for species with elongated fins and slow swimming.
It is best to keep them with tough active fish, such as Argus green, Indian shooter, Arius, Silver Spade and goby , such as Goby .
There is no documented successful breeding of this species and little information is available. According to a scientific article from 2014, an adult female can lay around 1,000 eggs. Hatching is characterized by a high survival rate. Successful reproduction took place in a 120 liter aquarium.
The fish were kept for one month in water with a salinity of 1.023 g / cm³, which during the following month was gradually reduced to the level of 1.007 g / cm³. Fish spawn directly on the ground or on a flat stone. Parents transfer the larvae to a previously dug depression in the substrate. The male protects the eggs and hatching.