Algae in a shrimp tank: match the response to what you see

Start with the animals and the type of growth. A coating on glass calls for a different response from spreading slime mats with distressed animals. Remove obstructive growth selectively and investigate lighting, plants and loading. Do not buy additional shrimp to clean up an unresolved problem.

What are you observing?

• Thin film, normal animals and dependable water readings: clean viewing surfaces as needed and follow development. Some accessible grazing surfaces can remain.
• Long green threads overgrowing plants: use the hair-algae route.
• Wipeable brown coating in a young aquarium: see brown films and diatoms; colour alone is not identification.
• Cohesive slime mats: use the possible-cyanobacteria route.
• Abnormal behaviour or deaths: promptly check temperature, filtration, gas exchange and ammonia/nitrite. Follow the problem-solving route.

Investigate recurring growth

Record actual lighting hours, direct sunlight, food, fertiliser, recent trimming and maintenance. Check whether the selected plants grow under those conditions. A nitrate or phosphate reading is one clue; no isolated reading establishes the cause or a universal target.

In an otherwise stable aquarium, change an explainable factor and compare photographs and new growth at the same location. Reduce leftovers without withholding needed food. Do not deliberately starve plants to eliminate every alga. Acute deterioration cannot wait for this comparison.

Neocaridina and Amano may graze particular surfaces, but do not make every alga edible or replace maintenance. Fan shrimp need suspended food. Do not select an algaecide or antibiotic from a photograph alone.

Sources and scope

• Aqueon: Prevention and control of nuisance algae
• UF/IFAS: Dissolved Oxygen for Fish Production
• UF/IFAS: Ammonia in Aquatic Systems
• UF/IFAS: Cherry shrimp, Neocaridina davidi

Aqueon supplies aquarium-manufacturer husbandry guidance. The observation and maintenance route is our editorial application. Appearance alone identifies neither an algal species nor safe water quality; fixed fish thresholds are not transferred to shrimp.