Wild Fact #459 – Catch of the Day – Paedocypris


Image credit: H. H. Tan, Raffles Museum of Biodiversity Research, National University of Singapore

It looks like we may have started a trend with Yesterday’s Wild Fact on the Bumblebee Bat as I now have a desire to continue talking about the Worlds Smallest animals. Today, we are heading to a forest swamp in Indonesia to learn about the Worlds Smallest Fish, the Paedocypris. In fact, this tiny fish just happens to be the smallest animal with a backbone on the face of the earth, that we know about. You had better grab your magnifying glass and rubber boots for this adventure because I have a hunch that you will need both to spot the Paedocypris.

Okay, we all want to know just how small this fish really is and I won’t keep you in suspense…….that long. First, I should tell you that this fish belongs to the family Cyprinidae which means Carp and Minnows, such as the Red-Sided Dace, are technically related to our World Record Holder. Interestingly enough, this tiny fish is very thin and is transparent. That’s right, you can actually see through them. So this may be pretty cool but do you want to know something even more amazing about the Paedocypris? Of course you do! These animals have a very “un-developed” skull and as a result their brain is exposed! So not only can you see through them but their brain isn’t fully enclosed by their skull. Tell me that doesn’t make this one of the best fish species on the planet?


Image credit: M. Kottelat, Raffles Museum of Biodiversity Research, National University of Singapore

If that doesn’t amaze you then maybe it is time to tell you how big this animal is. But first, I think you should know that the Paedocypris prefers to live in small, acidic swamps on the Indonesian Island of Sumatra. Oh and their is also another Paedocyrpis species that likes to hang out in peat swamps in Sarawak (that is in Borneo, folks). It is believed that the small size of this fish actually helps it survive since they don’t need a lot of water to live in, which is perfect considering that part of the world experiences severe droughts. Okay, one more crazy fact before I tell you their size. You know those acidic swamps this fish lives in? Well, the pH of these watering holes is around 2.9, which is basically equivalent to vinegar. That’s right, they are essentially living in vinegar! Cool fish, eh?

Paedocypris Fast Fact – All right, I will let you in on the size of the Worlds Smallest Fish but before I do I just wanted to tell you that…. nah, I am just kidding. The Paedocypris measures in at an astonishing 7.9 mm (0.31 inches), which is roughly the size of a large mosquito. I bet you won’t hear any fisherman bragging about that catch!

I hope you enjoyed another of the Worlds Smallest Wild Facts. Have a great day and I will see you tomorrow.

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