When choosing the most interesting photos from our expedition to Sulawesi in October 2023, I carefully tried to avoid pictures with non-native fish species. Believe me it was very difficult. But in the case of snails, shrimps, crabs and plants, it was just as possible. In this article, we will not completely avoid non-native and often downright harmful fish species, but we will still focus on the original, endemic fauna.

To get a general overview, I recommend the article "Endemic freshwater fish of Sulawesi".

Mugilogobius latifrons. This goby is endemic to Matano, Mahalona and Towuti lakes. It is a very little-known species, not imported for aquariums. I only saw this one individual, it was curious and we were examining each other.
Mugilogobius adeia. We found juveniles (about 1.5 cm in size) under stones in very shallow water. Lake Matano endemic, endangered species.
Glossogobius flavipinnis, another of Sulawesi's iconic species. So far, it has not been possible to raise offspring of this or other Sulawesi gobies in aquariums. Fortunately, it is still an abundant species in Lake Towuti.
Mugilogobius sarasinorum is probably the only goby still living in Lake Poso. It defies common notions that gobies are poor swimmers and stick to the bottom.
Now that we have visited Lake Poso, let's continue with the local halfbeaks Nomorhamphus celebensis. They don't behave according to preconceptions either – they hardly ever stay below the surface, on the contrary, they swim about 1-1.5 m deep in large shoals.
Nomorhamphus weberi is endemic to Lake Matano. Another beautiful halfbeak.
Endemics of the Sulawesi lakes from the Telmatheridae family (sailfin silversides) are, in addition to the numerous species of the genus Telmatherina, also the genera Tominanga and Paratherina. These fish are not kept in aquariums at all.
Telmatherina sarasinorum from Lake Matano. These fish are known for color polymorphism.
The same applies to Telmatherina antoniae 'small', also from Lake Matano. This tiny fish is very fast; when we post videos, you will be able to enjoy their beauty better.
Three species of ricefish live in Lake Towuti: Oryzias marmoratus, O. profundicola and O. loxolepis, which was described only this year. They are all very similar.
Ricefish fry of various species from Lake Poso congregate in mixed schools. When snorkeling, you can find yourself in the middle of hundreds of fish.
Lake Poso is home to seven endemic ricefish species (three of the genus Oryzias and four of the genus Adrianichthys, although at least one is believed to be extinct). Even adult fish gather in schools – if you find the right place, like these underwater caves, it's an amazing experience!
This last photo shows the fantastic density of ricefish of several species in Lake Poso. Unfortunately, the introduced cichlid species from Lake Malawi in Africa cannot be overlooked, but more on that later. Can you spot a crab skillfully climbing the rock?
See also the other selections of the best of the 2023 Sulawesi trip:

Markéta Rejlková