Black Skirt Tetra: tank size, group & compatibility data

Stocking notes

A robust schooling tetra that can nip slow or long-finned tankmates when under-grouped.

For planning, StockingLab models Black Skirt Tetra at its approximate adult size rather than the juvenile size commonly seen in shops. That matters because space use and waste production can change dramatically as fish mature.

What the calculator checks

• Whether the tank's usable volume is below the 75 L / 19.8 US gal reference minimum.
• Whether the selected group is below the planner's typical 6 fish social starting point.
• Whether target temperature and pH sit inside the planning range.
• Whether prospective tankmates create predation, fin-nipping, territorial or water-overlap conflicts.
• Whether too many fish accumulate in the same mid swim zone.

Before buying

Use this profile as a shortlist tool, not as a substitute for a dedicated care source. Confirm adult size, diet, sex ratio, habitat structure and locally relevant water conditions before purchase.

How to interpret this Black Skirt Tetra profile

At roughly 6 cm / 2.4 in adult length, Black Skirt Tetra should be planned at mature size rather than the smaller size commonly offered for sale. The reference tank is 75+ L / 19.8+ US gal, with a planning water window of 20–27°C and pH 6–7.5. A midpoint around 23.5°C and pH 6.8 is useful only as a comparison aid; the aim is stable water that overlaps the needs of the whole community.

The 6+ social starting point means tank size should be judged for the group, not for a single shop-sized fish. The modeled waste factor is 1.00×, so biological load is only one part of the decision; adult space, group size and swim-zone crowding still need to be checked. Activity is modeled at 1.10×, so the planner balances ordinary movement demand with adult size and mid-zone occupancy.

Common planning mistakes to avoid

• Keep the group at or above the 6+ planning starting point before adding extra species.
• Avoid slow or long-finned tankmates unless a dedicated species source supports the pairing and the tank provides enough space.
• Check that the planned temperature sits inside the shared 20–27°C range for every species in the community.
• Use the 75 L / 19.8 US gal reference as a starting point, then let actual tank dimensions, filtration and the full stock list refine the decision.

Bottom line: the profile is designed to screen a proposed aquarium for obvious pressure points. A result that passes StockingLab still needs to be checked against current, species-specific husbandry information for Gymnocorymbus ternetzi, especially diet, breeding behavior, sex ratio and habitat structure.