These are easy to tell apart. Only Cardinals have red all the way in the lower body half and only False Neons have the blue stripe extend all the way to the tail.

axelrodi
axelrodi

Cardinal Tetra

Discovered by Harld Sirtoli in September 1952. Popularized later by Herbert Axelrod for whom the fish is named.


innesi
longfin
albino
innesi

Neon Tetra

In 1935 Rabout discovered near Iquitos, Peru, some brightly colors small fish purely by chance: he was actually collecting butterflies. When a woman pointed out the brightly colored fish he knew a good thing when he saw it and was able was able to get 13 live specimens to Lepant in Paris, who gave them to J. S. Neel who named them "Neon Tetra". These fish were then sold to two Germans, Hugo Schnell and Walter Griem, in Hamburg for "$6500".

A year later in 1936, Walter Chute of the Shedd Aquarium in Chicago commissioned Fred Cochu to transport five Neons from Peru to the US on the airship Hindenburg; only one survived and the Hindenburg ended the use of hydrogen in transportation a year later in New Jersey. Because transportation from Peru to the US was "$3000" the single one of those fish that survived the most expensive fish known - houses cost less than that.

American Magazine publisher William T. Innes had also received (preserved) specimens from Rabaut for identification and gave them to George S. Myers who described them naming them after Innes in 1936.


simulans
simulans

False Neon Tetra

Discovered and named by Jacques Géry in 1963.


Species in Genus : Paracheirodon Refeences:
Catalog of Fishes:
axelrodi, Cheirodon Schultz [L. P.] 1956:42, Fig. [Tropical Fish Hobbyist v. 4 (no. 4); ref. 12224] Stream near Tomar, Rio Negro, near Porto Velho, Brazil. Holotype: USNM 164483. Paratypes: USNM 164484 (1). Type catalog and locality information: Vari & Howe 1991:14 [ref. 19022]. •Valid as Paracheirodon axelrodi (Schultz 1956) -- (Fuller et al. 1999:186 [ref. 25838], Malabarba in Reis et al. 2003:152-153 [ref. 27061], Mirande 2010:510 [ref. 31006], Marshall et al. 2012:378 [ref. 31785], Ohara et al. 2017:11 [ref. 35144], DoNascimiento et al. 2017:52 [ref. 35633]). Current status: Valid as Paracheirodon axelrodi (Schultz 1956). Characidae: Stethaprioninae. Distribution: Upper Orinoco and Negro River basins: Brazil, Colombia and Venezuela. Habitat: freshwater.

cardinalis, Hyphessobrycon Myers [G. S.] & Weitzman [S. H.] 1956:1 [Stanford Ichthyological Bulletin v. 7 (no. 1); ref. 12214] Stream near Tomar [Thomar], about 0°25'S, 63°55'S, Rio Negro, Amazonas, Brazil. Holotype: CAS-SU 48710. Paratypes: (10) CAS-SU 48711 (now 5), 48712 (2, c&s). •Synonym of Paracheirodon axelrodi (Schultz 1956) -- (Malabarba in Reis et al. 2003:153 [ref. 27061]). Current status: Synonym of Paracheirodon axelrodi (Schultz 1956). Characidae: Stethaprioninae. Habitat: freshwater.

innesi, Hyphessobrycon Myers [G. S.] 1936:97 [Proceedings of the Biological Society of Washington v. 49; ref. 13726] Likely near Iquitos, Peruvian Amazon. Holotype (unique): USNM 102109. Type catalog: Vari & Howe 1991:27 [ref. 19022]. •Valid as Hyphessobrycon innesi Myers 1936 -- (Schreitmüller 1936:501 [ref. 27793]). •Valid as Paracheirodon innesi (Myers 1936) -- (Ortega & Vari 1986:9 [ref. 9708], Fuller et al. 1999:186 [ref. 25838], Malabarba in Reis et al. 2003:153 [ref. 27061], Marshall et al. 2012:378 [ref. 31785], Marinho 2017:2 [ref. 35491], DoNascimiento et al. 2017:52 [ref. 35633]). Current status: Valid as Paracheirodon innesi (Myers 1936). Characidae: Stethaprioninae. Distribution: Tributaries of Solimõs River: Brazil, Colombia and Peru. Habitat: freshwater.

simulans, Hyphessobrycon Géry [J.] 1963:15, Figs. 1-3 [Tropical Fish Hobbyist v. 11 (no. 8) Apr.; ref. 4855] Rio Purus, Manaus, Brazil [corrected to River Jufaris, which empties into the Rio Negro just above Rio Branco]. Holotype: USNM 197510 [ex Géry coll. M.332.1]. Paratypes: Géry coll. M.332.2 (1), M.332.3 (1). Type catalog: Weber 1998:8 [ref. 23532] with holotype as MHNG 2171.19, Vari & Howe 1991:27 [ref. 19022] with locality information. •Valid as Paracheirodon simulans (Géry 1963) -- (Malabarba & Weitzman 1999:413 [ref. 24417], Fuller et al. 1999:186 [ref. 25838], Malabarba in Reis et al. 2003:153 [ref. 27061], Marshall et al. 2012:378 [ref. 31785], DoNascimiento et al. 2017:52 [ref. 35633]). Current status: Valid as Paracheirodon simulans (Géry 1963). Characidae: Stethaprioninae. Distribution: Upper Negro and Orinoco River basins: Brazil, Colombia and Venezuela. Habitat: freshwater.

Aqualog: The Neon Tetra – a fish that changed the world
http://www.aqualog.de/en/blog-en/the-neon-tetra-a-fish-that-changed-the-world

Sports Illustrated, 1965; "The Strange Fish and Stranger Times of Dr. Herbert R. Axelrod"
http://www.si.com/vault/1965/05/03/607350/the-strange-fish-and-stranger-times-of-dr-herbert-r-axelrod

New York Times Magazine - lives lived: Herbert R. Axelrod
https://www.nytimes.com/interactive/2017/12/28/magazine/the-lives-they-lived-herbert-r-axelrod.html