Fish with Ich Credit: Dehai Xu, Ph.D

According to new research presented by Dehai Xu, Ph.D. at the 240th National Meeting of the American Chemical Society (ACS)*, a vaccine against the feared ich disease might be available in the foreseeable future.

Ich is a disease dreaded by hobby aquarists and professional fish farmers alike. It is caused by the ciliated protozoan Ichthyophthirius multifiliis (hence the name ich) and can easily kill of all the fish in an aquarium or fish pond. Fortunately, it seems to be unable to infect humans. Among aquarists, it is chiefly known as White Spot Disease since the parasites cause small white nodules to form on the skin and in the gills of infested fish.

Today, ich outbreaks in large commercial fish farms are often treated by adding hundreds of gallons of a formaldehyde solution to the water. This is far from an ideal solution, since formaldehyde can be toxic to both humans and fish. It is classified as a known human carcinogen by the WHO International Agency for Research on Cancer (IARC) and is associated with both nasal sinus cancer and nasopharyngeal cancer. And as anyone who has ever combated ich in an aquarium knows, ich treatment is something you have to do over and over again since the parasite is usually only sensitive to treatment during one of its multiple life stages. This means repeatedly adding large quantities of formaldehyde solution to the pond. Even when formaldehyde ich treatment is successful, it provides no long-lasting effects since the fish develops no immunity. If new outbreaks occur, a new treatment cycle has to be carried out.

It is therefore no surprise that the series of vaccine tests carried out by Dr. Xu and his colleagues Dr. Phillip Klesius and Dr. Craig Shoemaker, who are with the U. S. Department of Agriculture’s Agricultural Research Service (ARS) in Alabama, have sparked vibrant interest within the aquatic world. For anyone from commercial fish farmers to public aquaria and hobby fish keepers, an ich vaccine would be a dream come true.

“Outbreaks of the parasitic disease caused by Ichthyophthirius (Ich) can result in losses of 50-100 percent of fish,” Dr Xu explained while presenting the team’s findings at the ACS meeting. “The disease is very common, and almost every home fish hobbyist has encountered it. Once the parasite infects fish, and starts growing in the skin, fins, and gills, there is no really effective treatment. Ich causes losses estimated at $50 million annually. It would be much better to prevent the disease. To vaccinate against Ich, you would need much less medication, and it would not pose an apparent threat to the environment. And you would need just one treatment to make the fish immune for life.”

In their efforts to develop a vaccine, Xu and his colleagues have focused on the use of so-called trophonts.

The ich protozoa goes though three life stages:

• The ich trophozoite feeds inside the nodule (”the white spot”) on the skin or gill of the fish.

• The ich trophozoite falls off and becomes an ich tomont, i.e. it enters an encapsulated dividing stage. During this stage, the tomont is attached to plants, gravel or other objects in the environment.

• The ich parasite will then start dividing itself, producing trophonts. The trophonts will move around freely in the water, looking for fish to infect.

Trophonts burrow into the skin and fills of a fish and start to feed, thus completing the cycle. When Xu, Klesius and Shoemaker began their research project very little was known about how fish develop protective immunity to trophonts, so the researchers basically had to start from scratch.

Eventually, they were able to show that vaccination with live ich theronts and trophonts killed with high-frequency sound waves stimulated production of protective antibodies in channel catfish (Ictalurus punctatus)

“This study demonstrated that vaccines against Ich induced protective immunity and could provide a unique solution to prevent this parasitic disease through vaccination,” Xu said. “An Ich vaccine would have great impact by preventing the disease, minimizing loss of valuable fish and increasing profitability of aquaculture.”

Injecting fish in a laboratory setting is one thing, administering a vaccine to thousands or even millions of fish in a huge commercial farm is another, so the next goal will be to find a way of carrying out large-scale vaccinations. It might for instance be possible to produce a large quantity of Ich antigen and then creating a vaccine that can be administered as food or in a “bath”.

For aquarists however, injecting each fish with the vaccine might actually be a feasible solution, provided of course that an injectable vaccine would be produced for the aquarium market.

* http://portal.acs.org

An aquarium fish has survived seven months in a fish tank without being fed or cared for, since its owner is in police custody after being accused of killing two Chilean students and wounding three others.

When employees from Contractor’s Choice and members of the Summer Lake Homeowners Association walked into the vacant town house at Miramar Beach, Florida, they discovered what appears to be a plecostomus.

The fish was apparently overlooked when lawmen removed the other pets – fish and birds – from the home after the arrest of the pet owner Dannie Baker. The fish went unnoticed for so long because Baker’s home was closed to the homeowners association after the arrest.

“I was very upset because I thought the police had taken everything after Dannie’s arrest,” said Dianne Richmond, vice president of the homeowners association. “This poor fish has been in that boiling house with no air conditioning and nothing to eat for about seven months.”

The pleco was discovered by the fiancée of Contractor’s Choice owner, who noticed something moving in the tank and sprinkled some fish food in the water. This caused the pleco to swim out into the open to feed.

When the pleco was discovered, much of the water in its tank had evaporated and the remaining water had turned dark.

Josh Olis, an account manager at Contractor’s Choice, said he didn’t believe it when his boss told him a fish was still alive in the tank. After seeing it for himself, he and the owner refilled the tank with about 50 gallons of water. He said he will make sure the fish is fed for as long as the company is working in the home. The contractors have even given the fish a name – Theo.

“I think we’re going to accept him into the cleaning family for now,” Olis said. “He’s been living in that tank for so long, surviving off algae. I have so much respect for him, I had to name him.”

The employees at Contractor’s Choice are now looking for a permanent home for Theo.

“This poor fish has really worked for a new home,” Richmond said. “It’s a wonder he’s survived this.”

AC Comment

Although I certainly don’t recommend neglecting your plecos for seven months, I’m not very surprised that Theo was alive and kicking when they found him. Many of the catfish species commonly referred to as plecos are algae-eaters (especially when young), so if there was any light coming into the room, Theo probably had some food to eat since nobody was there scrubbing away the algae. It all comes down to how large the tank is; a big tank may generate enough algae to keep a pleco alive (albeit hungry and malnourished) for several months.

Also, the natural habitat of plecos is Central and South America, so living without air conditioning in Florida is probably not something that bothered Theo much, especially if the aquarium was placed in a location where it was sheltered from sunlight during the harshest hours of the day.

Evaporation on the other hand, that is a real threat. The build up of waste in the water was probably tolerated by Theo since the progress was slow and gradual, but eventually ending up with hardly any water due to evaporation would naturally have killed him.

Last but not least, a word of caution. Although the employees of Contractor’s Choice acted admirably and should be applauded for taking such an interested in an abandoned fish, giving Theo 50 gallons of new water was actually quite risky since such a rapid change of water quality (and probably also temperature) can be lethal to fish – especially if the tap water is also heavily chlorinated. (But this is naturally impossible to know unless you’re an aquarist so I don’t mean to sound condescending here.) If you find a neglected fish, the safest method is to gradually change water quality and temperature until conditions are ideal for that particular species.

Several types of commonly used fish egg disinfectants increase the risk of swim bladder disorder in fish, a new study from Israel reveals.

In an effort to prevent fungal growth, many fish breeders use various chemicals, such as methylene blue, hydrogen peroxide, acriflavine and chloramine-T to aquariums where eggs are kept. This practise is especially common among breeders who will not let the parents stay with eggs and fry. Many fish species carry out parental care and eggs from such species often depend on one or both parents gently fanning fresh water over them and manually removing any unfertilized eggs from the batch. Without such parental care, the eggs easily succumb to fungi unless the fish breeder adds some type of fungicide to the water.

The new Israeli study, which focused on Angelfish (Pterophyllum scalare), revealed that some of these chemicals may be responsible for a swim bladder disorder in developing fish. In fish suffering from this type of disorder, the swim bladder can not inflate properly and the fry fails to develop into a fully free-swimming adult. Among aquarists, such fish are commonly known as “belly sliders” due to their peculiar way of moving around the fish tank.

Methylene blue

Eggs hatched in the presence of 1, 2 and 5 ppm methylene blue exhibited significant increases in swim bladder non-inflation (11%, 9% and 33%, respectively; none in controls).

Time of exposure to methylene blue was a key factor. Exposure for up to 1 day post-hatch did not affect swim bladder non-inflation, but exposure from 2 days onwards significantly increased swim bladder non-inflation.

Hydrogen peroxide

Hydrogen peroxide at 250 ppm significantly increased swim bladder non-inflation (65% comparing to 27% in the control). Higher concentrations resulted in 100% mortality.

Acriflavin

Exposure to acriflavin at 2.25 ppm, but not 1.25 ppm, significantly increased swim bladder non-inflation (75% and 52% respectively; 20% in controls).

Chloramin-T

Chloramine-T did not significantly affect swim bladder non-inflation.

For more information, see the paper “C. Sanabriaa, A. Diamantb and D. Zilberga (2009) – Effects of commonly used disinfectants and temperature on swim bladder non-inflation in freshwater angelfish, Pterophyllum scalare (Lichtenstein)”. The paper has been published in the journal Aquaculture.

The catfish L239 has finally been described by science and given a proper name: Baryancistrus beggini. Ichthyologists Lujan, Arce and Armbruster described the species in a paper[1] published in the journal Copeia[2].

Baryancistrus beggini lives in Venezuela and Colombia; in Rio Guaviare and at the confluence of Rio Ventuari and Rio Orinoco. The researchers found the fish in crevices amongst boulders. By analysing stomach contents, they were able to learn that this catfish feeds on periphyton and associated microfauna growing on rocks. (Periphyton is a mixture of algae, heterotrophic microbes, cyanobacteria, and detritus that can be found attached to submerged surfaces, e.g. stones, in most underwater ecosystems.)

In the aquarium trade, L239 is known as Blue panaque or Blue-fin panaque. The name beggini was given by Lujan and his colleagues in honour of Chris Beggin, the owner of an aquarium fish store in Nashville, USA who funded the research. The species has been placed in the genus Baryancistrus, but this might have to be corrected in the future as we learn more about the tribe Ancistrini.

Baryancistrus beggini sports a uniformly dark black to brown base colour with a blue sheen and the abdomen is naked. Along each side of the body you can see a distinctive keel above the pectoral finns; a keel formed by the strongly bent first three to five plates of the midventral series. The body also features two to three symmetrical and ordered predorsal plate rows and the last dorsal-fin ray is connected to the adipose fin.

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Loricariidae
Subfamily: Hypostominae
Tribe: Ancistrini
Genus: Baryancistrus

New species: Baryancistrus beggini