That Fish Blog – Aquarium Advice and Information

In our modern society, boys and girls are raised to be men and women and play equal roles in everything from defense to child-rearing. The animals kingdom isn’t as simple. With some animals, males and females have specific roles to play in their community and are nurtured for their positions. Many of the fish we keep in our aquariums have very different strategies. Weighing the balance between reproducing and surviving plays a huge part in their life history, right down to the most fundamental concepts of gender, size, and appearance.

A “hermaphrodite” is an organism that has both male and female reproductive abilities. While this is usually very rare in animals like birds and mammals, it is extremely common in plants and some invertebrates. Biologically speaking, if the chances of a plant or animal running across another of its kind are low, the chances of it finding another with the opposite sex as itself that it can reproduce with are even lower. Therefore, not having an assigned gender or being able to act as both genders can be beneficial. Many plants, animals and invertebrates use this strategy, but we’ll focus on fish in this blog.

Fish like wrasses, parrotfish, anthias and clownfish use “sequential hermaphroditism”, meaning that instead of having both sets of reproductive organs, the fish starts out as one gender and at some point is triggered to switch to another. There are two types of sequential hermaphroditism that we can witness in the aquarium trade:  protogyny and protandry. Read More »

Hello, Frank Indiviglio here.  Aquarists have long known that Discus Fish (Symphysodon spp.) produce mucus with which to feed their young.  However, recent studies revealed unexpected new parenting behaviors, leading some ichthyologists to compare them to mammals.  Just as surprising is the discovery that the European Eelpout (Zoarces viviparus), a commercially valuable marine fish, actually suckles it young with a milk-like secretion!

Weaning Behavior

The surprising new information about Discus appeared in the October 29, 2010 issue of the Journal of Experimental Biology.  While observing a breeding colony of the much-admired South American fishes, University of Plymouth (UK) biologists noticed that both parents avidly fed the young with mucus secretions for 2 weeks.  The fry were allowed to feed from an adult’s body for approximately 10 minutes, after which the ravenous little fellows were “flicked” onto the mate for more food.  Read More »

Having always kept saltwater tanks, I recently decided to try my hand at a freshwater planted tank.  Not having a lot of room to work with, I decided to set up a small, 2.5 gallon tank.  With such a small volume of water, I was limited in the fishthat I could keep, but I found a perfect fit for my new tank.

Dwarf Fighters (Betta rutilans) would be my new endeavor.  I researched the fish and took a look at the conditions of their native habitat in to get a better idea about how to furnish the tank. Betta rutilans comes from drainage basins in the Indonesian region and Borneo. They live in blackwater environments, where the water stays soft and acidic. These little guys only grow to a little over an inch in length, and they’re usually solid red or red with some green on their sides.  They have a longer and narrower body than Betta plendens, and have short, rounded fins like B. albimarginata. They can be housed with others of their kind. I’m hoping to see these fish spawn in the tank and I chose 1 male and 3 females to see how they get along.   Read More »

Hello everyone, some of our previous blogs have certainly talked about some scary-looking and bizarre fish! I thought I would add one more to the list -the Prehistoric Monster Fish, Thalassophryne amazonica.

The Prehistoric Monster Fish has a bizarre appearance that may make you wonder exactly what it is you are looking at. It comes from the Amazon River, where it lurks on the bottom waiting for unsuspecting prey. Its tan and brown coloration allows it to blend in with its sandy environment where it often buries itself, making it nearly invisible to other fish. At barely 6 inches long, this fish boasts a wide mouth that can easily swallow large prey.  Its eyes are situated on the top of its head to allow for a perfect view while it’s buried. To make it a bit more frightening, the Monster Fish has a venomous spine on each of its gill coverings and two in its dorsal fin. Monster Fish can inflict a painful sting, and while the venom is not terribly potent, it’s best not to handle them to avoid incident. Read More »

Hello, Frank Indiviglio here.  Seahorse identification is a tricky prospect, as most species can change color, and many even periodically grow and discard fleshy appendages known as cirri.  However, the husbandry needs of each species varies, so a proper ID is critical.  Fortunately, the Big-Bellied or Pot-Bellied Seahorse (Hippocampus abdominalis) is very distinct in appearance.

Description

At 12.5 inches in length, the Big-Bellied Seahorse is one of the largest (perhaps the largest) of the world’s 120+ seahorse species.  The body is noticeably deeper than that of other seahorses.  Males possess a huge brood pouch, which is usually white in color and bordered with yellow at the top.  Other distinguishing features are the number of dorsal fin rays (26-29), trunk rings (12-13) and tail rings (45-48), all of which exceed those of most other species. Read More »