A collection of frequently asked questions about marine fish care, covering acclimation, feeding, disease prevention, and more
The drip acclimation method is the safest. Transfer the fish with bag water into a bucket, then drip tank water via airline tubing at 2–3 drops per second. When the volume doubles or triples, discard excess and repeat. This takes 1–2 hours. Never add bag water to your tank — net the fish and transfer it alone. For details, see our Marine Fish Acclimation Guide.
Flake food and pellets are the staple diet. Supplement with frozen brine shrimp, copepods, or mysis shrimp 2–3 times a week. Herbivorous fish like tangs also need nori sheets. Feed twice a day, only what they can eat in 2–3 minutes, and remove uneaten food promptly to prevent water quality issues.
Maintaining stable water quality is the best prevention. Perform 10–15% weekly water changes, clean the protein skimmer, and maintain the filter regularly. Quarantine new fish for 2–4 weeks before adding them to the display tank. For more details, see our Marine Fish Disease Prevention & Treatment article.
Watch for territorial aggression between same or closely related species. Damselfish and clownfish can fight fiercely among their own kind. Avoid mixing large and small fish due to predation risk. Start with peaceful species and add aggressive ones last. If unsure, consult a breeder through our Marine Fish category.
Marine fish are shipped in bags filled with seawater and oxygen, in insulated styrofoam boxes with seasonal heat/cold packs. Schedule delivery when you'll be home and open promptly. Avoid redelivery — it stresses the fish. For details, see our Live Fish Shipping & Receiving Guide.
Essential equipment includes a tank (60 cm or larger), protein skimmer, heater and chiller, powerhead, lighting, hydrometer, and salt mix. Budget around $350–1,050 USD for a 60 cm setup. For a complete list, see our Marine Fish Equipment Guide.
Maintain specific gravity at 1.023–1.025, temperature at 24–26°C (75–79°F), and pH at 8.1–8.4. Ammonia and nitrite should read zero; keep nitrate below 20 ppm. Always top off evaporation with freshwater. Perform 10–15% weekly water changes and avoid sudden changes. For more, see our User Guide.
Ocellaris clownfish, blue-green chromis, firefish, and royal gramma are excellent beginner choices. Clownfish are famously hardy, and chromis are peaceful schooling fish. Start with 2–3 fish and add more every 1–2 weeks. Browse actual listings in our Marine Fish category.
On BreederDirect, you can buy marine fish directly from verified breeders. Health status and feeding information is accurate since breeders raise the fish themselves. Fair pricing with no middleman markups, plus post-purchase care advice. The escrow system ensures secure transactions. For details, see our User Guide.
Cycling takes a minimum of 3–6 weeks. Equipment setup and saltwater preparation take a day, followed by 3–4 weeks for the nitrogen cycle to establish. Rushing risks losing all your fish. For step-by-step instructions, see our Marine Fish Tank Setup Guide.