Everyone back up, this dartfish looks mad as heck

If fish had beds, this one woke up on the wrong side of hers. Meet Helfrich’s dartfish, a small marine fish with attitude to burn.
Contributor

Bec Crew

Contributor

Bec Crew

Becky Crew is a Sydney-based science communicator with a love for weird and wonderful animals. From strange behaviours and special adaptations to newly discovered species and the researchers who find them, her topics celebrate how alien yet relatable so many of the creatures that live amongst us can be.

By Bec Crew October 20, 2020 Reading Time: 2 Minutes

FOUND IN THE Pacific Ocean, with its range spanning Indonesia to the Tuamotu Archipelago of the French Polynesia, Helfrich’s dartfish (Nemateleotris helfrichi) has been recorded only a handful of times in Australian waters, just off the coast of Cairns.

While not actually cranky, these fish sure do look it. The purple stripe running down the species’ forehead is the exact same energy as sticking frowny eyebrows on a dog. And that downturned mouth would make Grumpy Cat proud.

True to its antisocial vibe, these fish form monogamous pairs and hide away in small caves together, occasionally sticking their discontented countenances out to scout for food. They’ll also fight other dartfish that stray into their territory, because of course they do.

Helfrich’s dartfish are carnivorous, and feed on all manner tiny creatures, such as zooplankton, crustaceans, and prawn larvae. Aquarium owners report that their colours fade if they’re not able to get enough nutrients from their diet.

Those colours are the reason these fish are considered one of the ‘holy grail’ species for tropical fish collectors.

You can see them even better here, the rich purple of the fish’s body contrasting beautifully with its bright yellow face and muted jade green fins and tail:

There is also a pink form, which is just stunning.

Dartfish belong to the Gobiidae family of bony fish, one of the largest known fish families, which encompasses more than 2,000 species.

There are just four known species in the dartfish genus Nemateleotris (also known as firefish) and they are all as gorgeous and cantankerous as each other.

Here’s an elegant firefish (Nemateleotris decora), native to tropical waters of the Indo-West Pacific, looking like she’s about to yell at the kids to get off her sea grass:

(Image credit: Chris Cheung/Shutterstock)

Check out her brilliant colours though.

Like Helfrich’s dartfish, the elegant firefish has been spotted a handful of times in Australian waters, off the coast of Cairns.

Here’s the exquisite firefish (Nemateleotris exquisita), found in the Indian Ocean. It looks so similar to the elegant firefish that, until 2013, researchers once thought they were the same species:

And here’s the magnificent firefish (Nemateleotris magnifica) native to the Indian and Pacific Oceans:

(Image credit: Claudine Lamothe/Flickr)

We’ll leave you with this footage of the magnificent firefish, really living up to its name: