Chilodus

This is an elegant, slender fish with a noticeable rise in its back, which culminates in the dorsal fin. The caudal fin is clearly divided into two lobes. The silvery body coloration is adorned with numerous dark speckles; in the central part, they are most densely arranged, forming a kind of horizontal line. The speckles continue onto the fins, which are usually transparent but sometimes acquire a reddish tint. Sexual dimorphism is weakly expressed. The dorsal fin of males is slightly higher than that of females, while females, in turn, are distinguished by more rounded forms.

This fish is widely distributed in the upper reaches of the Amazon River basin, covering the territories of modern-day Ecuador, Peru, and Brazil, and is also found in the Orinoco River system in Colombia. Its habitats include slow-flowing streams, tributaries, rivers, as well as oxbow lakes and flooded forest areas.

This is a peaceful but somewhat shy fish that requires calm and non-boisterous tankmates. Chilodus can be kept together with some South American cichlids, Corydoras catfish, and other peaceful Amazonian species. They prefer to stay in shoals of at least 10 individuals; with fewer numbers, especially in the presence of other fish, they may experience excessive stress.

A sufficiently spacious aquarium will be required for a group of fish. A volume of at least 200 liters is recommended if you plan to keep about 10 individuals. In terms of aquascaping, it is important to find a harmonious combination of open swimming areas and dense plantings of aquarium plants, maintaining a ratio of approximately 50/50. The presence of floating plants will be a plus, creating natural shading in the aquarium. Sand is suitable as a substrate. Various shelters should be placed on it: snags, branches, or tree roots. Adding several dried leaves to the bottom of the aquarium helps enrich the water with tannins as they decompose. This also gives the water a slight tint, mimicking the natural habitat conditions of Chilodus. Leaves should be replaced weekly. The water in the aquarium should be soft and slightly acidic, as determined by dGH and pH values. Detailed information on water parameters and methods for their adjustment can be found in the section "Hydrochemical composition of water." Minimal equipment includes an aerator, heater, lighting system, and filtration. Special requirements are placed on filtration: it is advisable to choose the most productive filter that fits your financial capabilities. Alder cone fillers can be added to the filter. They not only purify the water but also contribute to its acidification.

The diet for Chilodus should be varied, including both meaty and plant-based components. For example, bloodworms, daphnia, and brine shrimp can be used, supplemented with spirulina flakes, small pieces of cucumber, lettuce leaves, and some types of fruits characteristic of the Upper Amazon. Experimenting with the diet is recommended only for experienced aquarists; for others, specialized, high-quality foods from trusted manufacturers will be the optimal choice.

The breeding process for these fish is considered quite troublesome for most aquarists who, despite their love for their pets, are not willing to invest significant time and resources. Before spawning, the largest males and females are placed in separate tanks for 2–3 weeks, where they are fed live food intensively; dry packaged foods are not suitable during this period. They are then combined in a spawning tank — usually a container with a water level of up to 20 cm, which should be soft and acidic. No special decoration is required, but a fine-mesh net is recommended on the bottom to protect the eggs from being eaten. Essential equipment includes a simple sponge filter, an aerator, a low-power lighting system, and a heater. The water temperature is set 2–3 degrees higher than in the main aquarium. The future breeders are placed in the spawning tank in the evening to give them time to acclimate. Spawning may begin the next day, but sometimes a wait is necessary; in such a case, remember to feed them. After a brief courtship, each female lays up to 300 eggs. Without a protective net, the eggs will be eaten! The parents are returned to the main aquarium, and the eggs are transferred to a three-liter jar. The water level is maintained up to 5 cm, a weak aeration is set, and the temperature is kept around 28°C. Fry appear within 4–5 days; their growth is uneven, with some significantly outstripping others, but cannibalism has not been observed.

Chilodus are sensitive to water quality, particularly high nitrate content. Under poor keeping conditions, fish often exhibit bacterial fin rot, manifesting as their destruction or decay. To prevent diseases, effective filtration, regular aeration, and weekly partial water changes are necessary. The fish are susceptible to stress, so the presence of dense plant thickets where they can hide is an important condition for maintaining their immunity.

When purchasing, choose active fish with clean scales and clear fins without signs of film or damage. Healthy individuals should display typical species behavior: swimming in a shoal, holding their body at an angle with their head down, and actively exploring the bottom or middle layers of the water. Avoid specimens that appear emaciated, stay alone, or have unnatural spots on their body. It is recommended to acquire a group of 10–15 individuals at once, as fish experience severe stress and become extremely timid when alone.