Jewelled blenny (Salarias fasciatus) – an algae eater
The jewelled blenny (Salarias fasciatus), a member of the extensive Blenniidae family, is often recommended as a starter species for marine aquariums. Despite its relatively unremarkable coloration, this quirky fish serves an important role in the aquarium: consuming algae. Its English common name, “lawnmower blenny,” highlights this function. However, in my experience, this reputation is somewhat exaggerated. None of the Salarias I’ve kept consumed macroalgae; instead, they focused on scraping biological sediment from the glass and rocks.
Characteristics
The jewelled blenny is a graceful and sociable fish. Juveniles sold in stores are typically about 5 centimeters long, but under optimal aquarium conditions, they can grow significantly larger. With their elongated, cylindrical bodies, their size doesn’t necessarily correspond to their weight. These fish are known for their charming behavior. They love to perch in nooks and crannies, observing their surroundings with curiosity. Often, they can be found sitting near the front glass of the aquarium, seemingly watching the outside world, much like a dog watching its owner.
One interesting trait of the jewelled blenny, and many other blennies, is the absence of a swim bladder. As a result, they cannot float motionless in the water. Instead, after swimming a short distance, they settle on a rock or sand to explore their environment.
Despite their endearing qualities, jewelled blennies can show aggression toward other members of the Blenniidae family. Therefore, if you plan to keep them, it’s best to house just one individual in your aquarium.
While reports exist of successful breeding under specialized conditions, breeding jewelled blennies in amateur setups remains exceedingly rare.
It’s also worth noting their tendency to hide in crevices, including potentially dangerous spots like disabled water pumps or circulators. This behavior can pose significant risks, so careful attention to the aquarium setup is essential.
Diet
Like most members of the Blenniidae family, Salarias fasciatus primarily feeds on periphyton – a mix of organic sediments that grow on underwater rocks and plants. Periphyton consists of bacteria, algae, and small crustaceans. While the jewelled blenny is often mistaken for a strict herbivore, studies reveal that only about 15% of its diet consists of plant material.
His second passion, closely tied to aquariums, is diving, which offers him a deeper perspective on his hobby. Witnessing reefs and marine life in their natural environment inspires him to recreate aquariums that mirror nature as closely as possible.
For Bartek, writing about and promoting marine aquariums is not just about sharing technical knowledge. It is also about fostering environmental awareness among aquarists, emphasizing the importance of good practices, respect for nature, and reducing the ecological footprint of the hobby.
- Jewelled blenny (Salarias fasciatus) – an algae eater - September 15, 2025
- Apogons – Peaceful and Social Fish - June 9, 2025
- Chromis – Shooling in the Aquarium - April 29, 2025
