About Fins Up Reef Co. | Littleton Saltwater Aquarium Store

Plan your visit

Fins Up Reef Co. is a saltwater fish and aquarium store in Littleton, Colorado, owned by Ryan Cullen. We help reef keepers choose livestock, care for their aquariums and plan new systems, with aquarium maintenance for homes and businesses across the Denver area.

Visit your Littleton fish and reef shop

Explore corals, saltwater fish, invertebrates and aquarium supplies in person, or shop our WYSIWYG livestock online. WYSIWYG means you receive the exact specimen photographed in the listing. Selection changes as individual pieces sell.

Looking for a particular saltwater fish?

Visit our Littleton store to see the current selection, or send a saltwater fish request. Availability changes, so ask about the fish you have in mind before making a trip. We can discuss a quote and optional quarantine when you submit your request.

Inside our Littleton shop

Take a look around our reef displays and coral tanks. These photos show the shop, not individual WYSIWYG listings. Livestock pictured may not reflect current availability.

A reef display aquarium on a white cabinet inside Fins Up Reef Co.

Rows of corals in long reef aquariums under blue lighting at Fins Up Reef Co.

Two reef display aquariums with corals and fish inside Fins Up Reef Co.

Meet Ryan

Ryan works hands-on with the store’s reef systems and customer aquariums. Whether you are choosing your first coral, looking for a showpiece clam or troubleshooting your setup, bring your questions and tell us about your tank.

Care before the sale

Our coral quarantine process includes three weeks of milbemycin oxime treatment with weekly potassium chloride dips. It is intended to reduce pest risk, not guarantee pest-free livestock. Read about our coral quarantine process and your own inspection steps.

Aquarium services

We offer saltwater aquarium maintenance, new aquarium projects and tank moves. Contact us with your location, tank size and goals so we can confirm availability and provide a quote.