Welcome to Nate's...Guide to Fishes! Here you will find all sorts of interesting facts, information, and pictures about the denizens of the deep!

What's a fish?

This may seem like a simple question, but it's pretty complicated. Think of a fish! Tuna, Salmon, Pufferfish, doesn't matter, they're all fish! But go look in a mirror...and there's a fish staring back at you! That's right, you're a fish! Now I'm not saying you have gills and scales, but evolutionarily (and phylogenetically) you're considered a fish.

Let's imagine a phylogenetic (evolutionary) tree. (For an example of a simple tree, CLICK HERE). Phylogenetic trees describe relationships between groups of organisms, based on how similar the groups are to each other. Our tree has 3 animals: the a tuna (ray-finned fish), a coelacanth (lobe-finned fish), and YOU (a tetrapod)! There are 3 branches on this tree, with you and Mr. Coelacanth being more closely related (you have a more recent common ancestor) than either of you to Charlie Tuna. When scientists make these trees, they place organisms in groups that are MONOPHYLETIC. A monophyletic group is a group of organisms that includes a common ancestor, plus all of its descendents. Excluding a descendent or lineage forms a PARAPHYLETIC group, which is to be avoided at all costs. If we use this principle of monophyly, then we can form two groups: one including all tbree branches; the other, including only the coelacanth and ourselves. The first group is known as Osteichthyes (AKA bony fishes), and the second as Sarcopterygii (AKA lobe-finned fishes). However, if we were to group the tuna and the coelacanth together as "fishes" and exclude ourselves, this mean the group known as bony fishes is paraphyletic, and that's no good. To talk about fishes in the scientific sense, we must include ourselves in this group. Therefore, WE ARE FISH!

However, when I use the term fish on this site, I use it in the colloquial sense. Technically when scientists use paraphyletic terms, they should be in quotes (AKA "fishes"). My guide mentions only those organisms recognized as fishes by the average individual and excludes other organisms, such as turtles, birds, and even me or you. So the final answer is thus: a fish, in the non-phylogenetic sense, is an organism with a backbone, spends its life in water, and has fins, gills, and scales (of course there are exceptions to these "rules").

How many fish are there?

When I took my class on fishes at Cornell, it was estimated that there are about 30,000 species of fishes alive today. This can be compared to the number of vertebrates, which is approximately 60,000 species. This may seem like a lot (it is), but this does not even come close to the number of species of bacteria, fungi, or insects.

What's the difference between fish and fishes?

"Fish" is used when talking about one fish, such as the Barreleye. When we have a single Barreleye, we have a fish. When there are multiple Barreleyes (same species), we have multiple fish. When we have 1,000 Barreleye, and one Silverside, we have multiple fishes. See? Once multiple species are involved, we change from fish to fishes.

Why'd you make this website?

I've always had an interest in marine biology, especially fishes. My interest blossomed while at Cornell, where I did some fish phylogeny research on the evolution and development of the gasbladder. Although I will be pursuing a career in medicine instead of ichthyology, I want to find a way to show non-fish people how cool fishes are in an understandable, non-academic fashion. Every group of fishes has something fascinating to learn about and I want you to hear about it! If you leave this site thinking "wow, that's kind of cool," then my job is done.

How will this index work?

When you go to the index, you will find a list of fishes from class down to family. THe different levels of taxonomic classification are notated by differences in size and indentation. Clicking the links on the sidebar will take you to the different classes. Clicking on any of the black underlined links listed in the taxonomy will take you to a separate page, with more information about those specific groups. Extinct groups of fishes are also mentioned and notated in blue font.

Where is this information from? How do I know it's correct?

I haven't cited specific sources on each article, mostly because this is for fun and not a research paper. Regarding the classification, I used Nelson's 2006 edition of Fishes of the World. This provides the most comprehensive classification of all fish famillies, although more recent papers have made changes to the phylogenies. I have chosen to ignore some of the changes but used others depending on the day and my mood. For each entry, I used Nelson, Eschmeyer's Encyclopedia of Fishes, and The Diversity of Fishes, my class's textbook (plus liberal referencing of Wikipedia..sorry). I mentioned any relevant or pertinent sources that might be interesting.