Last May my wife and I spent a month traveling through Australia. One of the highlights was the chance to snorkel and dive in the Great Barrier Reef, something I looked forward to with great anticipation. Back in 1995 I had realized my dream of snorkeling in a reef, in Kenya. It was one of the most memorable experiences I’ve ever had. The Great Barrier Reef promised to be even better. Some club members asked if I would look for Australian rainbows, but I thought "Ya, right. Fat chance I’ll be diving in fresh water, or even be anywhere rainbows occur." As it turned out, I spent more time in or near clear fresh water streams than I did in the reef. And what do you know, there were lots of colorful fish with double dorsal fins swimming about. Yes, rainbows.

Unfortunately I made no preparations for this fresh water experience, aside from bringing my snorkeling gear. My other hobby, particularly when traveling, is bird watching. For that I spent countless hours pouring over Simpson and Day’s The Princeton Field Guide of the Birds of Australia. I had no time to browse through my Baensch Aquarium Atlas for Australian fish. The result was that I had little problem identifying the birds we came across, but I had to rely on my memory and the interpretive centers at the national parks to identify the fish we were seeing. Thankfully such centers had information on the fish most commonly seen.

My first encounter with typical Australian fish was on our second day in Australia. We went to the town of Kuranda, high in the Atherton Tablelands in northern Queensland. While waiting for a boat to tour the Barron River, I noticed some yellowish fish swimming about the dock. These proved to be rainbows, possibly the eastern rainbowfish (Melanotaenia splendida splendida). There was nothing splendid about these fish though, they were yellowish and without other bright coloration. The river bottom was sandy and the water was tea colored. Later, during the cruise, our guide pointed out some large dark fish that were good to eat when all of a sudden, SPLASH, a large archerfish decided to steal some of the bread crumbs from the other fish. The archer seemed to be over 30 cm long though the Baensch Aquarium Atlas quotes 27 cm for Toxotes chatareus, and 24 cm for T. jaculatrix (the two species of archerfish likely to be seen in Australia). What I found surprising is that I thought archerfish were only found in brackish water. But we were on a river, about 600 meters above sea level. Two days later I also found young archerfish swimming in the mangrove waters around the pier in Cairns.

The next encounter with freshwater fish came when we went to Kakadu and Lichfield National Parks. Both parks are in the Northern Territory of Australia, near Darwin. I was regretting the fact that we only had two days at the Great Barrier Reef when the tour operator suggested that I take my snorkel gear to Kakadu. "We have great swimming holes there", she said. And she was right. Australians seem to love water, and there is nothing more refreshing up north than a swim in the rivers, as long as there are no "salties" around. Salties are the saltwater crocodiles (Crocodilus porosus) and are the stuff nightmares are made of. The other species of crocodile, the fresh water or "freshie" (Crocodilus johnstoni), is not a problem as long as you keep your distance.

While on a hike in Kakadu we crossed a creek in a monsoon forest. It had crystal clear waters, no plants and a sandy bottom. There were lots of fish that resembled tiger barbs and some dark ones with the same shape. These turned out to be young of two species of grunter, the black-striped grunter (Amniataba percoides) and the sooty grunter (Bidyanus bidyanus). They proved to be very common and the black-striped grunters had the annoying habit of biting our legs when we were standing still in the water. Later I observed them picking algae from rocks, so they must have mistaken our legs for rocks! With the grunters were rainbows, this time the checkered rainbowfish (Melanotaenia splendida inornata), a splendidly plain fish! These were nicer than the ones in Kuranda, as they had bluish reflections on their fins. From above they were reminiscent of female green swordtails (Xiphophorus helleri) or green mollies (Poecilia velifera).

On our second day in Kakadu, Vanessa, our fearless guide, took us for a swim at Barramundi Gorge. After heeding the sign that there were freshies in the area, we began our hike. It was a great hike there, with a few crossings of Barramundi Creek, again with crystal clear water and the usual grunters and checkered rainbows. The gorge was very deep, the water was dark green but clear, surrounded by rock and a water fall at one end. As soon as I got into the water I noticed a couple of sooty grunters by the rocks, but as I pushed into the greenness I saw the unmistakable shape of a green arowana (Scleropages jardini) swimming away from me. The Australians call this fish saratoga. Later I observed another one probing the sand with its barbels. There was nothing else new to see here, the barramundi were not to be found.

We ended our tour of Kakadu with a swim at Gunlom Falls. For movie buffs this is where Mic "Crocodile" Dundee took his lady friend for a swim. The water here was clearer and colder than at Barramundi Gorge, and the fish life was much more interesting. For starters I found a fully grown male banded rainbowfish (Melanotaenia trifasciata) swimming in the creek. The blues and the reds reflecting from the fish as it moved between light and shade were simply incredible. It was then that I became a rainbowfish convert. Unfortunately there was no way for me to get into the creek and I didn’t find any rainbows in the lake below the falls. Both species of rainbows seen so far had a marked preference for moving water.

In the lake were salmon catfish (Arius leptapsis), eel-tailed catfish (Porochilus rendahli), long tom (a fish that looks like an overgrown half-beak), archerfish (Toxotes chatareus), and some young barramundi (Lates calcarifer). The barramundi, or simply barra, is a giant perch that can reach 180 cm in length. It is considered a great sport fish and it tastes great. I also got a very blurred underwater picture of some small fish. I believe these were some species of blue-eyes (Pseudomugil sp.). The only vegetation in the water were pandanus palms that grow at the water level. Their roots create cover for small fish to hide. There were also some submerged tree trunks, where I found most of the species of fish. Only the catfish and the grunters seemed keen on swimming in the wide-open areas.

The tour of Lichfield National Park should have been called a swimming tour, for aside from the driving and a short hike we went from swimming hole to swimming hole. No complaints from me, as it was a very hot day. In one of these places, Wangi Falls, the water was very clear and I got to see some gudgeons and what I believe was a sleepy cod (Oxyleotris lineolata). More grunters and checkered rainbows were to be found. I wish I wasn’t so drained from three days at Kakadu for there were great opportunities for finding other species of fish, and even swimming with some rainbows.

After Lichfield we headed into the interior and then south where it was either too dry or too cold to explore the creeks. Next time I’ll spend more time studying the fish and I’ll know what to expect. I consider myself very lucky to have had the opportunity to see these fish in their natural environment, and I’m looking forward to setting up a tank with rainbows. The funny thing is that I never paid attention to them before.

I will cover some of the marine fish from the Great Barrier Reef in Part 2.

Riehl, Rüdiger, & Baensch, Hans A. (1986). Aquarium Atlas. Melle, Germany: MERGUS-Verlag.

Riehl, Rüdiger, & Baensch, Hans A. (1993). Aquarium Atlas Volume 2. Melle, Germany: MERGUS-Verlag.