About the Julii Cory
Species Type: Freshwater Fish
Care Level: Moderate. May tolerate only a narrow range of water parameters, have specific dietary requirements including frozen or even live foods, may have behaviors that severely limit potential tankmates or may require a specialized aquarium setup.
Origin: A few coastal rivers and certain areas in the lower Amazon basin, Brazil. Occurs in small creeks, flooded forest, sandy pools.
Compatibility/Temperament: Very peaceful bottom fish, well suited to any community aquarium of non-aggressive fishes. Must be kept in a group, minimum three but preferably five or more. A group of three can be kept with other cory species, but given this species uniqueness, rarity and smaller size, a group of five would be ideal.
This is one of four very similarly-patterned corys that are frequently confused and will often be seen in stores under incorrect names. Corydoras julii, C. leopardus, C. punctatus and C. trilineatus all share a large black blotch in the dorsal fin, a barred caudal fin, and a horizontal stripe along the body at the juncture of the dorsal and ventral lateral plates; the body is spotted. However, all these species are highly variable in their pattern, and the horizontal stripe may be absent in C. julii.
The subject species is quite rare in the hobby, since it occurs in rivers and areas that are generally not heavily-fished commercially and is therefore seldom exported; the few times it does appear it has probably been collected in the Rio Para which is regularly fished. The "Julii" cory most often seen in stores is more likely to be C. trilineatus. The true C. julii has a spotted pattern on the head and body, and the lateral stripe is either not present or extends only midway along the body. The two attached photos illustrate both these variations. C. julii is also somewhat smaller and more compact-looking in size than C. trilineatus.
The aquarium should be well-planted with pieces of bogwood, a dark substrate (small gravel or sand, provided it is smooth-edged) with some open areas; like most other cory species, this one does not appreciate bright lighting. Females are rounder when viewed from above.
The Corydoras are quite sensitive to water parameters and quality, and highly intolerant of salt, chemicals and medications. Signs of stress usually begin with rapid respiration, then lethargy (often just "sitting" on plant leaves, wood or the substrate respirating heavily, sometimes near the surface) and sometimes rolling onto one side. At such signs, a partial water change of at least 50% with a good water conditioner should immediately be made, and appropriate steps taken to remove the cause. Any sudden fluctuation in water chemistry or temperature often induces shock, causing the fish to "faint" and fall over on its side. Corydoras introduced to new aquaria will settle in better if the tank is established; Cory's do not adjust well to a new aquarium with still-unstable water conditions and fluctuations.
The dorsal, pectoral and adipose fins are each preceded by a spine which is actually a hardened and modified ray; the pectoral fin spine can be "locked" into position by the fish; care must be taken when netting Cory's not to entangle these spines, which can also give the aquarist a nasty jab. They are believed to be a defense adaptation, to lodge the fish in the throat of a predator.
All species in the genus will periodically and fairly regularly swim quickly to the surface for a gulp of air. The fish swallows the air and blood vessels in the hind gut extract oxygen from the air; it is then expelled through the vent the next time the fish breaks the surface for another gulp of air. This adaptation is believed to have evolved so that the fish can survive in poorly-oxygenated water such as drying pools during the dry season. It is however essential to the fish's well-being that it regularly swallows air.
The genus name is derived from the Greek "cory" meaning helmet, and "doras" meaning skin, incorrectly used here for "armour"; it refers to the dual row of overlapping plates (instead of scales) along the body, comparable to a suit of armour. This species was described by F. Steindachner in 1906 from the type specimens collected in a creek flowing into the Rio Parnaiba near Alto Parnaiba, Brazil. The individual honoured in the species name is unknown.
Julii Cory Diet
In its habit, feeds on worms, crustaceans, insect larvae. Readily accepts prepared foods that sink such as tablet and pellet; frozen bloodworms and live worms are relished as treats.
Attains about 2.2 inches maximum.
Minimum Tank Suggestion
24 inches in length.
Ideal water parameters for Julii Cory
Soft (hardness up to 12 dGH) acidic to very slightly basic (pH to 7.2) water, temperature 22-26C/72-79F but not warmer. Given that available fish will be wild-caught, soft and acidic water is recommended for long-term health.