Thursday, June 18, 2015

EPAULETTE SHARK SEX

The author was fortunate enough to come across a pair of mating Raja epaulette 
sharks on a night dive. 

The epaulette sharks gained world-wide fame in 2006 when they were described as “walking sharks” by a group of ichthyologists sea rching for new species in West Papua (Irian Jaya). The media picked up on these “new walking sharks” not realizing these sharks had been familiar to those that are shark-inclined for centuries!  That said, their habit of “walking” is especially interesting. They crawl along the sea floor on their muscular pectoral and pelvic fins, preferring this form of locomotion to swimming (they will swim if they are trying to cover a greater distance more rapidly). Not only do their specialized fins make them ideally adapted to a benthic lifestyle, their serpentine-like body type means they are better-suited for crawling and slinking between and within reef fissures, coral branches and the limited confines of the home aquarium.

Monday, May 4, 2015

SAVAGE SOHAL!

video

There are a number of marine fishes that are renowned for their aggressive tendencies. One of these is the Sohal surgeonfish (Acanthurus sohal). This is truly a “bad boy” of the reef! The Sohal shown in this video (which was named Kevin by one of the patients at this rehab facility) was kept in a 700-gallon aquarium. It regularly dashed around your hand as you attempted to clean the aquarium, but it never brought its caudal peduncle spine to bear. However, it would nip your hand and forearms! Not only did it let the Reef Tectonics technician know that it was boss, it had a particular disdain for the magnet we used to clean the aquarium - as you will see if you watch this video. (Note: that this video was taken after the surgeonfish had calmed down a little bit - his initial attacks were even more savage!).  

THE LEAF SCORPIONFISH - KING OF CRYPSIS

 A beautiful pink leaf scorpionfish interacts with a light colored individual off  Ambon, Indonesia. The pink fish, which I would suggest is a male, flops from side-to-side in front of what may be a female individual. 

There are three things that are important in the life of a fish (or any other organism). One: to acquire something to eat. Two: to avoid being eaten. And three (if you succeed in getting enough nutrients and steer clear of your hungry neighbors): to reproduce. One thing that can help a fish to achieve the first two objectives is to look like something that it is not, like an algae encrusted rock or a toxic sponge. This antipredation/feeding adaptation is referred to as camouflage or crypsis. Crypsis can take one of two forms: either a fish can match its surroundings so it goes totally undetected (i.e., eucrypsis) or it can take on the appearance and actions of something inedible (i.e., masquerade). One of the best examples of eucrypsis in the coral reef community is the leaf scorpionfish (Taenianotus triacanthus). With its laterally compressed body and high dorsal fin it resembles a leaf or the frond of a macroalgae. It enhances its mimicry of plant material by rocking back and forth or by swaying from side-to-side.

CAUGHT-UP IN A WASPFISH STIING!

 The longfin waspfish is spectacular species that is not easy to keep in the home aquarium. At night it emerges from the sand and cruises just over the bottom hunting.

There are many of aquarists that are always in search of the bizarre. There are a number of scorpionfishes that fall into this category and some of these show-up in the aquarium stores from time to time. These fishes are like fine art - they don't move around much but they are beautiful to behold as they remain in repose on the bottom of the tank or on the rock-work.

Bristletooth Filefish - Anemone Terminator!

The glass anemone destroyer - the bristle-tail filefish (Acreichthys tomentosus)

A number of years ago, I shared information about the bristle-tail filefish (Acreichthys tomentosus) in a magazine article. I found that in Europe, that many aquarists included this species in their reef aquarium fish community to take care of both glass anemones (Aiptasia spp.) and the dreaded Majano anemones (Anemonia cf. majano). The European reef-keepers swore up and down that they did not harm other cnidarians in the tank. When originally introducing A. tomentosus as a potential reef aquarium inhabitant I did suggest that there was some data that they may pick at xeniid corals, leather corals and large-polyped stony corals. Since that time, I have kept a dozen of these fish in my own and customer aquariums and have found that they are not as trust-worthy as I had hoped. Yes, they love to munch on those annoying little anemones (at least some individuals anyway), but they also might nip at the tentacles of more desirable sea anemones (e.g., Entacmaea quadricolor), the tips of gorgonian branches and the fleshy polyps of a variety of large-polyped stony corals (e.g., Acanthastrea, Turbinaria, Lobophyllia, Trachyphyllia).

HARLEQUIN SHRIMPS: Beautiful but Barbarous!

 "Oh what pretty tube-feet you have!" A pair of harlequin shrimp on a rubble patch off the coast of Sulawesi are having a Linkia seastar for dinner. 

The beautiful harlequin shrimps have often been considered as a difficult crustacean to care for. In actuality, they are very easy to  keep as long as you meet their specialized nutritional need – that is, provide them with sea star flesh! The harlequin shrimp are members of the family Hymenoceridae and the genus Hymenocera. Some crustacean experts think there is only one species in this genus, while others split the Indo-west Pacific and central and eastern Pacific forms (the former is recognized as Hymenocera elegans while the latter would be H. picta). Both “species” of harlequin shrimp are white to cream overall with large purplish blotches with blue margins (H. elegans) or maroon with yellow margins (H. picta).

TRIGGERS IN THE REEF TANK

 The redtooth or niger triggerfish (Odonus niger) is a handsome fish that can be kept in a reef aquarium. Of all the potentially reef-safe triggerfishes, this is one with a more dubious reputation. It will eat ornamental crustaceans and as it grows larger, it may attack and even kill fish tankmates.

Triggerfishes have long had a bad reputation for being voracious predators and aquarium bullies. Many of the triggers are some of the most polyphagous of all fishes, eating everything from algae, sponges and corals, to all kinds of crustaceans and even smaller fishes. So the idea of adding one of these beasts to a reef aquarium, packed with succulent invertebrates, seems a bit daft! While it is true, the majority of triggerfishes are not appropriate invertebrate aquarium neighbors,  there is a relatively small group of triggers that have more specialized diets that can be housed with sessile invertebrates. 
In this post we will examine these triggerfishes and look at the calculated risk of keeping some of the less suitable species with your invertebrates.