The Muddy Mystery

by Inspector Barry Mins on January 11, 2022

I know I left that list here somewhere. I have to get this week’s article written, and I can’t do it without knowing what I’m supposed to write about! Those kids are waiting on me. It was right here on the desk! What could have happened to it? Wait a minute . . . what’s this? It looks like . . . a gob of mud? How did that get here? And why is there a trail of mud and water leading towards the door? Something is not right here! Best get the magnifying glass out and have a look at this.

Hmm . . . those look like . . . fin marks? But the door is hundreds of yards from the water’s edge . . . what fish could survive out of water for a trip that long? And how could it climb up onto my desk? And why the mud? I need to follow this trail. Let’s see . . . it goes out the door . . . down the steps . . . how can fish navigate steps?! What is this, a flying fish? Let’s see . . . oh, bother. This is a clever little fish. He went right through the sprinkler and covered his trail perfectly—what a little rascal.

I’d better go inside and draw up a suspect profile with what I have. Let’s see.

  • Fish
  • Can live out of water for a long time
  • Can crawl across land
  • Can jump several feet
  • Likes mud
  • Can climb

Let me see what the computer tells me here. The tracks are too small for a bichir, snakehead, walking catfish, lungfish, or epaulette shark. We can rule them out. So what does that leave us?

  • Leaping blenny
  • Rockskipper
  • Mudskipper
  • Climbing gourami
  • Mangrove Rivulus
  • European and American eels
  • Wooly sculpin

Hmm . . . leaping blennies, wooly sculpins, and rockskippers need to stay moist . . . we’re too far from the beach to guarantee that, so we can rule them out. Eels slither, but these tracks look more like shuffling, so it was not an eel. Mangrove rivulus are possible, but these tracks were made by a fish with an extended body, and they have a normal fish body. We can rule out the rivulus. That leaves the climbing gourami and the mudskipper. Mudskipper . . . mudskipper . . . the mud on my desk . . . that’s got to be it!

Suspect Profile: Mudskipper


Gold-Spotted Mudskipper (Periophthalmus chrysospilos)
anukma, CC BY 4.0, via Wikimedia Commons

The mudskipper is a fish that can reach up to a foot long, with large bulging eyes that allow it to see above and below water at the same time. They have specialized pectoral fins they use to stabilize themselves in water and propel themselves on land.1 They eat small plankton that they pick off the substrate.2 Other species have broader diets, including smaller fish, crabs, and land insects.3 They prefer to feed during the day, though sometimes they will feed at night.4 They live in burrows dug from the mud and sometimes build little mud walls to protect their territory from neighboring mudskippers.5 To communicate on land, mudskippers produce sounds that can travel through wet sediment for short distances.6

Mudskippers lay eggs on land, but when it is time for the eggs to hatch, they will allow the eggs to be covered with water, causing them to hatch.7 The female will lay tens of thousands of eggs that the male will then fertilize.8

Try out this fun mudskipper crossword puzzle!

Perfect! I’ve got my suspect. Now to head out to the mudflats and get my list back! Normal articles will resume next week.


  1. C.M. Pace and A.C. Gibb “Mudskipper pectoral fin kinematics in aquatic and terrestrial environments.” The Journal of Experimental Biology, 212 (2009), 2279-2286.
  2. A.L. Sarker, N.K. Al-Daham, and M.N. Bhatti. “Food habits of the mudskipper, Pseudapocryptes dentatus (Val.).” Journal of Fish Biology, 17, no. 6 (1980) 635-639.
  3. Q.M. Dinh, L.T. Tran, T.T.M. Tran, D.K. To, T.T.K. Nguyen, and D.D. Tran. “Variation in diet composition of the mudskipper, Periophthalmodon septemradiatus, from Hau river, Vietnam.” Bulletin of Marine Science, 96, 3 (2020), 487-500.
  4. I. Colombini, R. Berti, A. Nocita, and L. Chelazzi. “Foraging strategy of the mudskipper Preiophthalmus sobrinus Eggert in a Kenyan mangrove.” Journal of Experimental Marine Biology and Ecology, 197, (1996), 219-235.
  5. D.A. Clayton, and T.C. Vaugh. “Territorial acquisition in the mudskipper Boleophtalmus boddarti (Teleostei, Gobiidae) on the mudflats of Kuwait.” Journal of the Zoological Society of London, 209, (1986) 501-519.
  6. G. Polgar, S. Malavasi, G. Cipolato, V. Georgalas, J.A. Clack, and P. Torricelli. “Acoustic communication at the water’s edge: evolutionary insights from a mudskipper.” PLoS One, 2011.
  7. A. Ishimatsu, Y. Yoshida, N. Itoki, T. Takeda, H.J. Lee, and J.B. Graham. “Mudskippers brood their eggs in air but submerge them for hatching.” The Journal of Experimental Biology, 210, (2007), 3946-3954.
  8. D.M. Quang, N.T.T. Giang, and N.T.K. Tien. “Reproductive biology of the mudskipper Boleophthalmus boddarti in soc trang.” Tap Chi Sinh Hoc, 37, 3 (2015), 362-369.