Articles by Jay Hemdal
The Weedy Scorpionfish
Rhinopias frondosa
Jay Hemdal
C. 2026
The outrageous looking Weedy Scorpionfish; with their lacy fins, grotesque mouth, goggle eyes and fabulous colors; a magnificent fish in anyone’s opinion. You see their picture in virtually every marine aquarium fish book, their...
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Please see the PDF link in the righthand column for the full article.
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Batfish and Spadefish in Aquariums
Jay Hemdal
Batfish and spadefish, especially juvenile specimens, have been popular with home aquarists ever since the early days of marine fish importations from the Philippine Islands in the late 1950’s. During the 1970’s three species of batfish were...
This article describes an issue termed the “Unknown Vesicle Disease” (UVD). It is characterized by one or more clear to translucent fluid-filled “bubbles” on the skin of certain species of fish. The cause of these vesicles is unknown. The outcome of infected fish varies; in some cases, the...
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This file is an adaptation of my university lecture on marine fish diseases. It includes a variety of links to Reef2Reef files for additional information. This file is a converted PowerPoint file made into a PDF. It may not work on all platforms. Click and download the PDF file on the...
Lymphocystis (cauliflower disease)
This is a common viral disease of marine, brackish, and certain freshwater fishes (usually those with marine relatives: glassfish and rainbowfish). It is a chronic (long-lasting) but self-limiting (usually going away on its own) syndrome caused by an...
Basslets—the Peaceful Groupers
By Jay Hemdal and Jeff Kurtz
Reef aquarists are ever on the lookout for fish species that will coexist peacefully with the corals and other prized invertebrates in their aquariums. It’s even more advantageous—for fish and reef keeper alike—if the particular...
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Fish Issue Case Histories – test your knowledge!
The following are a series of case histories regarding problems with aquatic animals. Each scenario results in a question as to how the particular event transpired. With the clues given, you can test your aquarium knowledge and reasoning...
The Undeniable Appeal of Puffers and Porcupines
By Jay Hemdal and Jeff Kurtz
Aquarists who are looking for a truly “pet-like” marine fish with loads of personality, a nimble brain (for a fish, anyway), wild coloration and patterning, and a body plan that borders on the bizarre, just might find...
Garden Eels
Jay Hemdal
Photo by Johan Fredriksson
Diving off New Providence Island in the Bahamas some 35 years ago, I swam above a sandy plain near a coral reef, towards what looked to me like a scattered field of seagrass. As I approached the area, the grass seemed to be getting shorter and...
Ozone, (O3) has the same elemental composition as oxygen, (O2) but very different chemical properties. Ozone, (tri-atomic oxygen) is a very unstable molecule. It is a powerful oxidizer. When ozone comes in contact with a compound exhibiting an “oxygen demand”, it releases one of its oxygen...
Aquarium Humor (barely)
For some aquarists, “aquarium humor” is an oxymoron, like “jumbo shrimp” or “military intelligence”. They take their hobby or vocation so seriously that they would never dream of equating their aquariums with humor in any form. However, comedy is a particularly unique...
The Red-rimmed Batfish, Platax pinnatus
Jay Hemdal
Photo by: "desertnaturalist"
Unfortunate experiences that people have had with this fish have taught most experienced aquarists to be very wary of this species. Large individuals, (8 to 12 inches tall) fare especially poorly. In speaking...
The Magnificent Bluestriped Angelfish, Chaetodontoplus septentrionalis
Jay Hemdal
2024 Update: This is a reprint of an article I wrote in 2006. The information has been reviewed for needed changes and updates. One important update is that Bali Aquarich has been producing this and related...
Aquatic Invasive Species
Jay Hemdal
Introduction –
Humans have moved plants and animals knowingly (and unknowingly) from one location on Earth to another for tens of thousands of years. The argument can be made that there has never been a translocation of a species that did not in some way...
Drum and Croaker
http://drumandcroaker.org/
Drum and Croaker is a non-peer-reviewed journal that has acted as an "informal organ" for public aquarium professionals since 1958. It has a long history of providing a forum for the exchange of basic information - and occasional humor. It was...
This article is a bit of a mashup – combining portions of a previous public aquarium article on animal sustainability, with some longevity data and fish pricing through the supply chain. To read the article, click on the PDF link to the right of the page.
MARINE FISH AND INVERTEBRATES TO AVOID
While selecting good quality animals and then properly quarantining them is vital for acquiring long-lived specimens for your aquarium, some species start the process with one or more strikes against them. Knowing which species have extra challenges helps...
Using “Artificial Intelligence” resources to treat fish diseases
With the development and release of ChatGPT in 2022, “AI” as an informational resource is becoming more commonplace. This term is in quotes because the current methods are not true Artificial Intelligence. Instead, what the...
Aquarium Myths and Misinformation
c. 2023 Jay Hemdal
Over the last 50 years, I’ve heard a number of myths and possible misinformation applied to aquariums and the husbandry of the animals contained in them. Most of these seem to go unchallenged; at least they keep showing up online, long...
