Oscars (also called velvet cichlids) get very large for freshwater pet fish — fourteen inches from nose to tail is not uncommon. Part of the reason for their large size and their incredible strength is because they eat smaller fish. There is no such thing as a vegetarian Oscar. Although I have never seen an Oscar take down a cow, I would not be surprised if that should happen someday. But all cattle need not be worried about being hunted by Oscars just yet.
A Separate Tank
When you bring an Oscar into your life, you need at least a fifty gallon aquarium for one Oscar. If your Oscar is currently a baby, do not wait too long before setting up the larger aquarium. Baby Oscars grow quickly and before you know it, he’s bursting out of the tank. Any other fish in that tank will be promptly eaten.
But you don’t have to get rid of the smaller tank. You will need that to stock part of the food for your Oscar. When Oscars are babies, they like cichlid pellets, bloodworms and brine shrimp. But as they get older, they need bigger food. Since they are meat eaters, you need to give them a variety of meats to eat including feeder goldfish or minnows.
Some Oscar keepers don’t recommend feeder goldfish in case you know without a shadow of a doubt that the feeder goldfish are healthy. Any illness that the feeder fish has will be instantly transmitted to your Oscar. Never feed dead fish as they will definitely harbor bacteria that will get your Oscar very sick (if he doesn’t ignore the carcass altogether.)
There are more options open to pet Oscars than ever before. They love pinches of raw hamburger, chicken, feeder crickets, worms, live bugs and frozen peas for dessert. Don’t just grab a random bug and throw it into the tank. That bug may have just walked through toxic chemicals and might have eaten a bad diet. You are not only throwing in the bug, but anything on (or inside of) that bug.
There are many feeder insects and worms of various lengths and widths available from bait stores and pet stores. Some people also grow their own worms (perhaps in the drained smaller tank the baby Oscar swam in).
Oscars will often gobble down pieces of bread, but this is not a good food for them. They also shouldn’t be given sugary foods or really starchy foods like French fries. This is like eating candy bars for dinner and can get your Oscar sick.
You should offer food to your Oscar at least once a day. They tend to swallow the food as soon as it hits the water. They are usually not a fish that likes to toy with their prey. If they have not eaten the food in two minutes, then they are not hungry and won’t change their minds. Remove the food, or the rotting food could negatively alter the water chemistry and get your Oscar sick.
“Oscars.” Neal Proneck. TFH Publications; 1993
FishLore.com. “Oscar Fish.” http://www.fishlore.com/Profiles-Oscar.htm
First Tank Guide. “Oscar Care Basics.” Keith Sayffarth. http://www.firsttankguide.net/oscar.php
Author’s personal experience.