Infolific » Freshwater Fish in the Wild

How Fish Use Electricity to Hunt and Communicate

Max Lepley — Sat, 05 Jan 2013 11:13:15 +0000

All fishes produce a slight electric field as a by-product of the nervous impulses intrinsic to life. However, some species have harnessed and concentrated this ability to enable them to communicate among themselves, to locate prey and, in some cases, to deliver a powerful shock to subdue other animals. Which [...]

Underwater Eating

Max Lepley — Sun, 16 Dec 2012 03:41:48 +0000

The importance of our hands for feeding ourselves is huge. We use them to catch food, to process it, and to carry it to our mouths, where we can hold it in place while we bite it. It may be obvious to point out that fish lack arms, yet this [...]

Prey Fish Avoid Predators By Hiding

Max Lepley — Tue, 04 Dec 2012 11:52:38 +0000

Fish can also avoid the attentions of their predators by hiding whenever danger threatens. They can do this either by seeking cover in the substrate or among rocks; or fleeing to places where their hunters cannot follow. For example, fish may choose to tough it out in an inhospitable environment, [...]

Rhythms of Underwater Life

Max Lepley — Mon, 03 Dec 2012 23:43:43 +0000

All life on earth is governed by rhythms, such as the day-night cycle or the changing of the seasons, and fish are no exception. These rhythms predict when fish are most active, when they eat and sleep and when they migrate and breed. Fish have three main aims over the [...]

Things You Didn't Know About Schooling Fish

Max Lepley — Mon, 12 Nov 2012 16:49:01 +0000

A huge number of different fish school. It is estimated that over half of the 25,000 or so known fish species school at some point during their lives. The incredibly widespread use of this strategy among fish species is an indication of its value. Schooling provides individual fish with significant [...]

How Fish Use Camouflage to Avoid Detection

Max Lepley — Sun, 11 Nov 2012 04:06:16 +0000

When predators are at large, it obviously pays to be inconspicuous. One way is to blend into the background, hoping to avoid detection by a hunter. Camouflage, or crypsis, is used widely by fish species for this purpose. A fish whose color matches its environment will live a great deal [...]

Fish in Their World

Max Lepley — Mon, 29 Oct 2012 22:56:44 +0000

Fish are among the most diverse of all animals. They are found in a huge variety of shapes, sizes, and colors, each perfectly fitted to the role they fill within their habitat, enabling them not only to survive, but to prosper. The way in which all animals, including fish, perceive [...]

General Recognition

Max Lepley — Sat, 29 Sep 2012 04:20:29 +0000

While to us it may be difficult to tell apart fish of the same species -- even sometimes of different species -- it is important for the fishes themselves to be able to do so. For example, fish that reacted in the same way to a predator as to a [...]

Fish Learning and Intelligence

Max Lepley — Mon, 17 Sep 2012 14:31:39 +0000

Are fish intelligent? Most people think not, believing that goldfish have only a three-second memory. Yet evidence shows that goldfish -- indeed all fish species have a far greater memory than this, plus a remarkable capacity for learning. Learning -- the modification of a response as a result of experience [...]

Piranha and Pacu

Max Lepley — Thu, 13 Sep 2012 17:57:24 +0000

While the majority of fish species concentrate their efforts on bite-sized invertebrates, small fish or plant matter, there are other options for the more adventurous piscine diners. This is exemplified by two very closely related South American characins, the red-bellied piranha (Pygocentrus nattereri) and the tambacqui, or pacu (Colossoma spp.), [...]

Synchronized Swimming

Max Lepley — Wed, 12 Sep 2012 11:04:01 +0000

One of the most arresting sights in the whole animal kingdom is that of a school of fish turning this way and that in perfect harmony with their schoolmates. It seems almost impossible to believe that an animal supposedly as simple as a fish could execute such a well-choreographed routine [...]

Invertebrate Eating Fish

Max Lepley — Fri, 31 Aug 2012 10:15:10 +0000

What could be better than to snack on a spider or feast on a fly larva? You and I might disagree, but invertebrates of all kinds are the food of choice for countless fish species. They represent nutritious, bite-sized morsels for many aquarium fishes. How do invertebrates try to stay [...]

Juvenile Fish

Max Lepley — Tue, 28 Aug 2012 20:07:22 +0000

Early in its life, a fish makes the transformation from larva to juvenile; for the first time in its life, it now looks like a miniature version of its own parents. This change is sometimes described as a metamorphosis, although the changes that occur in fish at this time are [...]

River Habitats

Max Lepley — Sat, 25 Aug 2012 17:44:32 +0000

Most of the familiar fish kept by aquarists, from tetras to rasboras and from angelfish to many of the well-known catfish, are native to rivers across the tropics. Some of these rivers are huge -- the Amazon river alone holds within its banks an incredible 20% of all the worlds [...]

Chemical Messages Underwater

Max Lepley — Tue, 21 Aug 2012 02:40:58 +0000

Fish detect the chemical cues that surround them using both their senses of smell (olfaction) and taste (gustation). Of these two, olfaction is considered the most important, especially over long distances. Fish use taste to assess things that are physically in contact with the taste cells. The underwater environment is [...]

Defensive Armor in Freshwater Fish

Max Lepley — Mon, 06 Aug 2012 04:44:05 +0000

Of course, not every fish darts away as a predator approaches. Some fish have evolved armor and other defenses, most often in the shape of spines, to make all but the meanest of predators seek their dinner elsewhere. But if it is so effective, why have not all fish evolved [...]

Behavioral Defense

Max Lepley — Tue, 17 Jul 2012 17:22:22 +0000

Even if the predator does detect its prey, the game is far from up. Fish have a variety of behavioral strategies available to them to avoid ending up as lunch. Beyond this, fish populations that co-exist with large numbers of predators often show adaptations that help them cope with this [...]

Fish Instinct and Learning From Experience

Max Lepley — Sat, 07 Jul 2012 17:04:30 +0000

In the wild, animals are continuously presented with new challenges and threats. To be successful, they must learn how to cope with these and how to respond to each novel situation. Overwhelming evidence now exists to show that, in common with so-called higher animals, such as mammals, fish are able [...]

Chemical Messages Between Fish

Max Lepley — Wed, 04 Jul 2012 04:02:49 +0000

Fish not only use their sense of smell to find food and stay around their home range, but also to pick up the chemical messages passed from fish to fish. These chemical messages -- more correctly called pheromones (from the Greek "pherein" meaning "to carry") -- allow fish to gather [...]

How Do Fish Detect Sound?

Max Lepley — Thu, 21 Jun 2012 12:21:13 +0000

Until relatively recently, fish were considered to be silent creatures; they clearly do not have external ears and even though they do have some internal hearing apparatus, it lacks some basic structures. But experiments performed early in the 20th century showed that fish could be trained to emerge to feed [...]