Maximum size : 5.5 cm

Blacktop Corydoras - Corydoras acutus : Complete Fish Profile & Care Guide

Table of contents


Blacktop Corydoras are excellent bottom-dwellers for scavenging leftover food, so your aquarium will remain cleaner and healthier. In addition, most community aquariums would benefit from these attractive and peaceful Corys. Finally, as they are shoaling species in nature, Fairy Corys will be much more active and confident if kept in groups of at least six. In addition to small to medium Tetras, Danios, Rasboras and Livebearers, Blacktop Corys will also do well with Gouramis, Dwarf Cichlids, Loaches and other peaceful Catfish. However, it would be best if you did not house them with anything aggressive or large. If you intend to breed these Corys, you should keep them in a species-only aquarium to prevent other greedy fish from eating their eggs. In an aquarium that mimics its natural habitat, Blacktop Corys will thrive. To achieve this, you could use a sandy substrate and add some driftwood; standard beech is also ok to use if you thoroughly dry it and strip it of its bark. Having dim lighting will also benefit your fish. Adding dried leaves to stain the water would complete the natural feel; however, you must replace them every few weeks, so they do not rot and pollute the water. Adding some aquarium-safe peat to the filter can aid in simulating black water conditions. Although you will not find aquatic plants in this Cory's natural waters, they also enjoy a well-planted aquarium. The Blacktop Corydoras is sensitive to deteriorating water conditions; therefore, a good maintenance schedule is essential. Like all Corys, this species may lose their barbels if you keep them in poor water, so make sure you keep the substrate clean and perform regular significant water changes. In some individuals, Blacktop Corys have a black blotch on their dorsal fin, while other individuals do not. However, their primary colour is light olive, and they have a faint pale band on each side with dark scales almost appearing as very small patches. The Caudal fin is divided into four vertical bars, while the clavicle and operculum have blue reflections.

Blacktop Corydoras Photos

Sexual Dimorphism

It is usually relatively easy to distinguish between male and female Blacktop Corydoras when adequately conditioned. Females will look much broader when viewed from the top, as they have a larger underbelly. In addition, males are shorter than females in length.

Quick Facts

Scientific NameCorydoras acutus
Year Described1872
Other NamesNone
OriginsEcuador , Peru , Brazil
Max Size5.5 cm
Aquarium LevelBottom
DifficultyBeginner - Intermediate
Best kept asGroups 6+
Diet & FeedingOmnivore
ReproductionEgg Depositor
Lifespan8 - 12 years

Water Parameters

Water TypeFreshwater
pH 6.0 - 8.0
GH 2 - 25
TDS 36 - 215
Ideal Temperature
71 - 82
21.7 - 27.8

Natural Habitat

The Blacktop Corydoras originate in inland waters in South America and are found in the Amazon River basin in Ecuador and Northern Peru. These Corys have also been recorded in the Machado River basin in Rondônia State in Brazil. These Corys inhabit very fast-flowing blackwaters in floodplain lakes and small forest streams with a white sandy substrate. These habitats do not have much aquatic vegetation; however, they have an abundance of submerged wood, driftwood and leaf litter.


Blacktop Corys will produce similar to other Corys. It would be best to set up a separate breeding tank with either a bare bottom, sand, or fine gravel substrate, and it would also help if you added an air-powered sponge filter and some clumps of java moss. For more successful results, you should have a higher ratio of males to females when breeding Corys; two males for every female is ideal. Finally, it would be better to condition the group on a mixed diet of dried, live and frozen foods, as this will help to encourage spawning. Once you can see the females are full of eggs, you should perform a significant water change with cooler water and increase the flow and oxygenation in the tank, then repeat this daily until the fish spawn. When the fish are ready to spawn, you may notice an increase in activity; this will be the males pursuing the females. When the females are prepared to spawn, they will allow the male to touch her with their barbels, where they will then take up the classic T-position. The female will then form a basket with her pelvic fins where she will place 1 to 4 eggs. Once the eggs are fertilised, she will swim away and find a suitable place to deposit the eggs, usually on the tank's glass near the water with a fast current. This cycle is then repeated until she has no more eggs. Once spawning is complete, you should remove either the adults or the eggs; otherwise, the parents will consume them. If you decide to move the eggs, you will find they are pretty strong and can be easily rolled up the glass with a finger. The new tank should be oxygenated and have the same water parameters as the breeding tank. It would be better to add a few drops of methylene blue to the water to prevent the eggs from getting fungus; however, some eggs may still have fungus, so you must remove them straight away to prevent it from spreading. The eggs will usually hatch between 3 and 5 days later, and the fry will initially feed on their yolk sacs. Once they have finished their yolk sacs, you will need to provide them with microworms and baby brine shrimp. The babies appear less susceptible to disease if you keep them in a tank with a thin layer of sand rather than a bare bottom. Then, once the fry grows a little larger and other fish won't see them as a snack, you can introduce them to a community aquarium.

Diet & feeding

In the home aquarium, Blacktop Corydoras will readily accept most good quality dried foods such as granules, flakes and sinking pellets. These modern food products have been developed to provide all adequate nutrition to maintain your fish's health and dietary requirements. Providing additional foodstuffs such as live, frozen, and freeze-dried meals such as bloodworm, daphnia, and tubifex once or twice a week will provide other benefits to your fish's health and well-being but is not a must for this fish. It should be noted that bloodworms should only be given as an occasional treat and should not be used as the staple diet as they are difficult for fish to digest and can potentially cause blockages. This fish is an omnivore in the wild, consuming some vegetable matter. Although most modern fish foods take this into account and include them in their products, you can still supplement your fish's diet with blanched vegetables such as spinach, broccoli, and zucchini. Ensure you do not overfeed your fish and remove any leftovers the following day.

Other Corydoras of interest