![Bruno Melo on Twitter: "Today is the π day so here is Protocheirodon pi (Vari, 1978), the Amazon Crystal Tetra with a modified swim bladder: a smaller anterior chamber and two vertically Bruno Melo on Twitter: "Today is the π day so here is Protocheirodon pi (Vari, 1978), the Amazon Crystal Tetra with a modified swim bladder: a smaller anterior chamber and two vertically](https://pbs.twimg.com/media/EwenO6xWEAIEpBa.jpg)
Bruno Melo on Twitter: "Today is the π day so here is Protocheirodon pi (Vari, 1978), the Amazon Crystal Tetra with a modified swim bladder: a smaller anterior chamber and two vertically
![Rare aquarium fish mountain crystal tetra (Leptagoniates pi) in well planted aquarium Stock Photo - Alamy Rare aquarium fish mountain crystal tetra (Leptagoniates pi) in well planted aquarium Stock Photo - Alamy](https://c8.alamy.com/comp/H2P0AK/rare-aquarium-fish-mountain-crystal-tetra-leptagoniates-pi-in-well-H2P0AK.jpg)
Rare aquarium fish mountain crystal tetra (Leptagoniates pi) in well planted aquarium Stock Photo - Alamy
![Amazon glass tetra (Phenacogaster pectinatus, Tetragonopterus pec.) | Fresh water fish tank, Pet fish, Tetra fish Amazon glass tetra (Phenacogaster pectinatus, Tetragonopterus pec.) | Fresh water fish tank, Pet fish, Tetra fish](https://i.pinimg.com/736x/d7/bb/03/d7bb038e57c82e617f01e1670a257331.jpg)
Amazon glass tetra (Phenacogaster pectinatus, Tetragonopterus pec.) | Fresh water fish tank, Pet fish, Tetra fish
![SciELO - Brasil - Protocheirodon, a new genus of Characidae (Teleostei: Characiformes) with the redescription of the poorly known Protocheirodon pi Protocheirodon, a new genus of Characidae (Teleostei: Characiformes) with the redescription SciELO - Brasil - Protocheirodon, a new genus of Characidae (Teleostei: Characiformes) with the redescription of the poorly known Protocheirodon pi Protocheirodon, a new genus of Characidae (Teleostei: Characiformes) with the redescription](https://minio.scielo.br/documentstore/1982-0224/9GXpcVxqbqrbkb44rt8Pgzn/f66fdee545b98d563b66c5376ec9081d4ba1f1f0.jpg)