Longfin Oscar (Astronotus ocellatus)

The Longfin Oscar (Astronotus ocellatus) is the same big, clever, wet pet cichlid as the classic Oscar, bred for long, flowing fins that trail behind it like a veil. These are a mixed color lot, so the group in our tank can include tiger, red, albino, and lemon patterns, and you get to pick the one that catches your eye. Like every Oscar it learns who feeds it, begs at the glass, and redecorates its own tank. It also grows fast and grows big, so it is a fish you plan a tank around rather than one you add to a tank you already have. Browse the rest of our freshwater livestock and supplies and our full fish collection.

What the Long Fins Change

Underneath the fins this is a standard Astronotus ocellatus, so size, diet, water, and temperament are the same as our Tiger Oscar and Snow White Albino Oscar. The fins do add three things to think about. Long fins tear on sharp rock and rough decor, so choose smooth stone and driftwood. Torn or ragged fins are also the first place poor water shows up as fin rot, which makes a clean tank even more important than it is for a short finned Oscar. Finally, a longfin swims a touch slower, so it can lose out at feeding time to a fast, pushy tankmate and is an easy target for any fish that likes to nip.

Care Guide

• Tank size: 75 gallons for a single adult, with 125 gallons or more for a pair or an Oscar with large tankmates. A juvenile can start smaller, but it will outgrow a small tank within months.
• Filtration: Oscars are messy eaters that produce a lot of waste. Run a canister such as the Sicce Whale Canister Filter or Aquatop Forza Canister Filter rated well above the tank size.
• Water changes: 30 to 50 percent weekly. High nitrate over time is linked to hole in the head disease and fin rot, and a longfin shows fin damage fast. Treat new water with Seachem Prime.
• Water parameters: 74 to 81°F, pH 6.0 to 8.0. Stability matters more than hitting a perfect number.
• Feeding: a quality cichlid pellet as the staple, such as Hikari Cichlid Gold or Hikari Cichlid Excel, with frozen krill as a treat. Feed juveniles small amounts two or three times a day and adults once a day. Skip feeder goldfish, which carry disease and offer poor nutrition.
• Decor: smooth rock, driftwood, and heavy ornaments that cannot be tipped. Oscars dig and move things, and loose plants will be uprooted. Keep sharp edges out of the tank for the sake of the fins.
• Lid: Oscars can jump, especially when startled. Keep the tank covered.

Specifications

Compatibility

Many keepers give an Oscar a tank of its own, and honestly that is the simplest way to keep one happy. If you want company, tankmates need to be too big to swallow, calm enough not to pick at long fins, and the tank needs to be large. Other Oscars, including our Tiger Oscar, are the classic pairing in a big enough tank. A school of full grown Silver Dollars works well as dither fish once the Oscar and the dollars are close in size.

What goes wrong: anything small enough to fit in its mouth, which includes tetras, guppies, rasboras, small corys, and shrimp, will eventually be eaten. Fin nippers such as tiger barbs and serpae tetras will shred those long fins. Very aggressive cichlids will bully a slower longfin at the food. Small plecos and snails often end up as snacks, and live plants are usually dug up.

Recommended Foods & Supplies

• Hikari Cichlid Gold Pellet everyday staple that brings out color
• Hikari Cichlid Excel to rotate in some plant matter
• SFBB Krill Cube frozen treat a couple of times a week
• Sicce Whale Canister Filter for the heavy waste load
• Hikari Texas Holey Rock Cave smooth, heavy decor it cannot tip
• Fritz Nitrate Test Kit to keep an eye on the number that matters most

FAQ

Which color will I get?
These come in as a mixed color lot, so what is in the tank varies from week to week. Come by and pick the one you like, or ask us what is in stock right now.

How big will it get, and how fast?
10 to 12 inches as an adult, and a healthy juvenile can grow about an inch a month early on. Buy the adult tank first, or at least have it planned.

Is a longfin harder to keep than a regular Oscar?
Slightly. Everything is the same except the fins, which need smooth decor, clean water, and tankmates that will not nip. If your water changes are consistent, a longfin is no more work than a standard Oscar.

My Oscar is lying on its side after I moved the rocks. Is it dying?
Usually not. Oscars are famous for sulking, lying still or going pale after a water change, a rearrangement, or a scare. Test the water to be sure, keep the lights low, and it normally bounces back within a day.

Can I feed it feeder fish?
We do not recommend it. Feeder fish are a common source of parasites and disease, and they are poor nutrition compared to a good pellet. Oscars take pellets eagerly.