Freshwater aquarium algae

Species may be unintentionally disseminated through spores and fragments that hitchhike on ornamental fish and plants purchased from aquarium suppliers.

Green algae respond strongly to bright light conditions as well as unbalanced carbon dioxide and nutrient levels in the water of freshwater aquaria.

[3] Green dust algae (GDA) is similar to GSA, however it adheres less aggressively and may be easily wiped off of the glass and substrate on which it settles.

[5] It is often seen in newly established aquaria and can also be a symptom of low carbon dioxide and nutrient levels in the water.

It is a very common infestation to have in newly established aquaria, but may also occur after temperature swings or nutrient imbalances.

[10] Green thread algae is common in newly established aquaria and is easily outcompeted by installed plants.

It spreads in the hobby aquaria trade through fragments disseminated on contaminated aquarium plants.

[12] It may grow in association with marimo, an algal ball which is intentionally cultivated in hobby aquaria.

[2] Zhan et al. (2020), using DNA barcoding, found 13 different operational taxonomic units of red algae growing within freshwater aquarium stores in Taiwan.

[1][a] Staghorn algae of the genus Compsopogon may exist on aquarium substrates and can be epiphytic on slow-growing plants.

[15] It is considered one of the more difficult species to remove, and the plants may uptake calcium from hard water which makes them unpalatable to algivores.

[16] Red spot algae may form a tenacious reddish-brown splotch or film on aquarium glass or plant leaves.

[18] Species in the genus Caloglossa, specifically C. beccarii and C. fluviatilis, are available from commercial aquarium dealers.

While there are many BGA species, the most common type found in aquaria is referred to as "slime algae".

True brown algae of the class Phaeophyceae are not known nuisance plants of freshwater aquaria.