Oscar: tank size, group & compatibility data

Stocking notes

A large predatory cichlid with heavy waste production and substantial space requirements.

For planning, StockingLab models Oscar 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 280 L / 74 US gal reference minimum.
• Whether the selected group is below the planner's typical 1 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 Oscar profile

At roughly 35 cm / 13.8 in adult length, Oscar should be planned at mature size rather than the smaller size commonly offered for sale. The reference tank is 280+ L / 74.0+ US gal, with a planning water window of 23–28°C and pH 6–8. A midpoint around 25.5°C and pH 7.0 is useful only as a comparison aid; the aim is stable water that overlaps the needs of the whole community.

The profile does not assume a school. Individual temperament, territory and the rest of the community therefore matter more than simply increasing numbers. Its relative waste factor of 2.80× is on the higher side in the StockingLab model, so filtration margin and maintenance become especially important as the fish reach adult size. Activity is modeled at 0.80×, so the planner balances ordinary movement demand with adult size and mid-zone occupancy.

Common planning mistakes to avoid

• Provide visual breaks and enough territory so one fish cannot control the whole footprint.
• Do not rely on water-parameter overlap alone when smaller tankmates may be viewed as prey.
• Check that the planned temperature sits inside the shared 23–28°C range for every species in the community.
• Use the 280 L / 74.0 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 Astronotus ocellatus, especially diet, breeding behavior, sex ratio and habitat structure.