About Underground Aquarium

Underground Aquarium is a home base for aquarium hobbyists, built by hobbyists. It brings free local classifieds, a care library, forums, a feed, planning tools and a directory of independent fish stores together in one place, and it's home to the Underground Aquarium Society.

What is Underground Aquarium?

The information fish keepers need tends to be scattered across forums, outdated care sheets and word of mouth, and the best local fish stores are hard to find unless someone tips you off. Underground Aquarium pulls it together: buy and sell with other keepers near you, look up honest care info, plan a tank before you spend anything, share what you're keeping, and find independent shops worth the drive.

Our About page tells the story in our own words: "Built by hobbyists, for hobbyists."

What can I do on Underground Aquarium?

Buy, sell and trade locally

The Classifieds are free local ads for fish, shrimp, snails, plants, coral, tanks and gear, organized by state and metro area. Buyers and sellers message each other on the site and arrange the rest themselves. See Posting a classified ad and Browsing classifieds.

Talk with other keepers

• The Feed: post photos, share your tanks and follow what others are building. See The feed.
• Forums: ask questions and get help from people who have kept it before. See Forums overview.
• Events: swaps, auctions, meetups and expos near you. See Finding events.
• Messages: private conversations with other members. See Messages overview.

Learn and plan

• Fish Species: honest care profiles with real adult size, temperament and tank minimums.
• Tank Builder: plan a stocking list and catch aggression, bioload and size problems before you buy.
• Water Check: log your water test results and get a straight answer about what's wrong.
• Glossary, Breeding Guides and Courses.

Find a fish store

The fish store directory lists independent aquarium shops (no chains) with hours, directions, reviews and updates from the owners. Shops Near Me sorts them by distance. See Finding a fish store.

Earn bubbles and trophies

You earn bubbles (reputation points) and trophies for taking part. They show on your public profile. See Bubbles and Trophies.

What is the Underground Aquarium Society?

The Society is our membership club for serious keepers: one national society with no chapters. Members log spawns, have them peer reviewed and judged in the Breeder Award Program, earn signed certificates that anyone can check on the Certificate Registry, and collect Society trophies. Membership has dues. See The Society overview.

Is Underground Aquarium free?

Yes. Creating an account, browsing, posting classified ads, messaging, the feed, the forums, the tools, the courses and the store directory are all free. Classified ads have no listing fee, no commission and never need a card.

The paid parts are optional:

• The Society has membership dues (yearly, with a one-time lifetime option). See Society dues and renewal.
• Clubs on the site can collect their own dues from their members. See Clubs.

Store owners can claim and manage their shop's page for free. See Claiming your store.

Do I need an account?

You can browse listings, read the feed and forums, look up species, use the Tank Builder and search the store directory without one. You'll need a free account to post, send messages, leave reviews, follow people and shops, earn bubbles and trophies, and join the Society. See Creating an account.

Who can use Underground Aquarium?

Anyone 18 or older. Everyone confirms they're at least 18 and agrees to the Terms of Service and Privacy Policy when creating an account. The classifieds are organized by US state and metro area. See Community rules for how we expect members to treat each other.

Does Underground Aquarium sell fish or handle payments for ads?

No. We don't sell livestock or gear ourselves, and we don't take part in classified ad sales. Buyers and sellers deal with each other directly, usually by meeting up locally. See Contacting a seller and Safe local pickup.

Why "independent" fish stores only?

Independent fish stores keep healthy stock, share hard-won advice and build the local community. Our directory points people to real local shops worth visiting and is free for shops to claim, update and use to reply to reviews.

Is there an app?

There's no app store download. The website works on any phone, and you can add it to your home screen so it opens like an app. See Using the site on your phone.

How do I find my way around?

On a computer, use the top menu (Feed, Forums, Classifieds, Shops Near Me, The Society and More). On a phone, use the bottom bar (Feed, Classifieds, +, Messages, Me) and the menu button. See Getting around the site.

How do I give feedback or get in touch?

We're building this in the open with the community, and we want to hear from you. Email support@undergroundaquarium.com with ideas, problems or a shop that should be listed. See Contacting support. To tell us about a missing shop, you can also use Suggesting a store.

Common problems

I'm looking for something that isn't in the top menu. Check More in the top menu on a computer, or the menu button on a phone. The footer at the bottom of every page has more links. See Getting around the site.

I don't know what a word on the site means. See Site terms explained for site words like bubbles, areas and spawn logs, or the Glossary for fish keeping terms.

Someone asked me to pay a fee to list or buy through Underground Aquarium. We never charge fees for classified ads. Don't pay anyone who says otherwise, and report the message. See Reporting content.