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Aquarium Setup
Choosing Freshwater Fish

Fish from either the tetra or danio family are excellent choices as first fish. The first fish should be added approximately 3 days after the aquarium is set up.

You should wait about a week before adding more fish. Then, add fish slowly, 3 to 5 at a time, and wait about a week between additions.

Getting Started with a Freshwater Aquarium
1. Aquarium Water
2. Choosing Freshwater Fish
3. Aquariums & Stands
4. Hoods & Lighting
5. Heaters & Thermometers
6. Air Pumps & Accessories
7. Filters
8. Gravel & Décor

After 4 to 6 weeks, the beneficial bacteria have been established and the cycle of setting up a new aquarium is complete!

Here are some types of fish you will find at your local PETCO store.
  • Calico Fantail Goldfish
  • Chinese Algae Eater
  • Danio Zebra [good first fish!]
  • Fantail Goldfish
  • Neon Tetra [good first fish!]
  • Painted Glass Fish
  • Plecostomus
  • Red-Eyed Tetra [good first fish!]
  • Serpae Tetra [good first fish!]
Community and Aggressive Fish

Some species of fish are more aggressive by nature and others are more peaceful. In our stores, PETCO has organized community and aggressive fish by section.

Community fish can coexist peacefully with members of their own species and other species of similar size. Examples of Community Fish are:
  • Tetras
  • Mollies
  • Platies
  • Goldfish
Aggressive fish are aggressive toward their own species and/or other species, regardless of their size. Examples of Aggressive Fish are:
  • African Cichlids
  • South American Cichlids
  • Oscars
  • Devils
There are levels of peacefulness and aggressiveness that exist within these two classifications. Depending on the environment and whether they are provoked, an aggressive-type fish may never exhibit aggressive behavior. Much of a fish's behavior depends on its relative size compared to other fish in the aquarium. Larger fish tend to intimidate smaller fish, making the small fish more aggressive.

Livebearers or Eggbearers

Fish that do not lay eggs, but produce live baby fish, are called livebearers. Once the babies are born, they do not need to be taken care of by their parents. Baby fish do, however, need an environment where they can hide and protect themselves from bigger fish. Examples of livebearers are platies and mollies.

Fish that lay eggs and fertilize them outside of their body are called eggbearers. Unlike livebearer baby fish, eggbearer baby fish rely on their parents for food and protection. Most of the fish PETCO sells are eggbearers.

When visiting your local PETCO, please ask a knowledgeable Aquatic Specialist for assistance with selecting the best fish for your aquarium.

Step 3: Aquariums & Stands