The Fish Vet's Blog

The question I received on email today:

I had someone ask me the other day about Siamese Fighting Fish, and the best way that they should be housed. It basically stemmed from the fact that this person had seen at a local petshop a fishtank filled with different kinds of fish, also containing 3 very small transparent boxes each with a Fighting fish in it. She was concerned that this was poor animal welfare for the fish. So, I was just wondering what sized tanks Fighting Fish need, whether they need to be housed alone/just away from other Fighting Fish/ or can be housed in sight of other Fighting Fish.

My response:

Siamese fighters are adapted to surviving in small puddles seasonally (when the water bodies dry up) and would prefer larger bodies of water to live in. As their name suggests, they are from the tropics (Siam is old for Thailand) and so they ought to be kept in water at a temperature of around 24degC. This can be maintained either with a heater in the water, a heated pad beneath the tank or by warming up the room.

There’s a great article written by my colleague on this issue in koi fish on page 16 of this newsletter –

http://www.wavma.org/media/Documents-for-download/AVN-2011-5(2).pdf

I suspect this research paper (link to the paper) had its roots in ornamental freshwater fish breeding since the culture methods for vinegar eels is in virtually every fish breeding text that’s out there. When I was younger, I often wondered what are these vinegar eels? Where do they come from? Do they just materialised out of thin air? Just some apple cider vinegar or oatmeal and you get microworms or vinegar eels.

This comment was by Wadim Kapulkin on my Facebook Fanpage. He has great insight and thought I’d share it on my other social media platforms. Thanks Wadim!

facebook Wadim Kapulkin commented on The Fish Vet‘s link. Wadim wrote: "Live feeds are essential in larval nutrition of many fish and crustacean species. As the consumers’ demand for aquaculture products is growing rapidly, the demand for live feeds in larviculture is increasing as well. To satisfy the growing demand, research has taken steps to develop new innovative live feeds. Several studies focused on nematodes as a potential food source for larvae. Production methods, culture media, harvest, and enrichment procedures for nematodes presented in these studies are reviewed here. Many studies fed nematodes to different species of fish and crustaceans to test applicability in larval nutrition. The results of these feeding trials in terms of larval performance as well as ingestion and digestion of nematodes in the larvae’s gut are reviewed here as well. In addition, a summary of advantages and disadvantages of nematodes as live food and an outlook on future challenges of production and application of nematodes in larviculture are also presented. In summary, several different production methods including innovative culture media for nematodes have been developed. The species Panagrellus redivivus has been used in most of the reviewed studies. It reproduces extremely fast and can be cultivated by very simple means of production. Other species such as Turbatrix aceti and Caenorhabditis elegans have been tested in a few studies as well. However, a complete production cycle for mass production appropriate for use in aquaculture has not been developed yet for any of these species. Enrichment trials for amino acids revealed only a very limited potential to manipulate amino acid profiles in nematodes. In contrast, fatty acid composition turned out to be quite variable depending on the culture media used for nematode production. By adding oils containing large quantities of essential fatty acids to the culture media, these fatty acids could be enriched in nematodes and provided to larvae. This allows tailoring fatty acid composition according to the needs of the respective larvae. It could be shown that nematodes can be digested by fish larvae even though they possess a robust cuticle. Larval performance depends strongly on the respective species of fish to which the nematodes are fed. Nematodes seemed to work particularly well for crustacean larvae. In penaeid larvae, nematodes turned out to be a good live food that can compete with conventional feeding methods even though there is still room for improvements. For future use in larviculture, appropriate methods for mass production, harvest, and feeding need to be developed. Additionally, more data on optimized feeding levels for different fish and crustacean species will be required." —

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Yours sincerely,

Dr Richmond Loh
BSc, BVMS, MPhil (Vet Path), MANZCVS (Aquatics), MANZCVS (Pathobiology), DipPM.
Veterinarian | Adjunct Senior Lecturer Murdoch University | WAVMA President-Elect |
Secretary Aquatic Animal Health Chapter – Australian and New Zealand College of Veterinary Scientists (ANZCVS)
The Fish Vet, Perth, Western Australia, AUSTRALIA. Mobile Veterinary Medical & Diagnostic Services for fish and other aquatic creatures.
http://www.thefishvet.com.au
Ph: +61 (0)421 822 383

Innovative solution to the issue of everyone wanting their share of artemia.

Journal of the World Aquaculture Society
Volume 43, Number 6 (December 2012)
	Nematodes as Live Food in Larviculture – A Review
	Authors:	Jens Brüggemann 1
	Author Affiliations:	1: Institute for Marine Resources (IMARE), Bussestr. 27, 27570 Bremerhaven, Germany
	Source:	Journal of the World Aquaculture Society, Volume 43, Number 6 (December 2012)
	Page Numbers:	739 – 763
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	Live feeds are essential in larval nutrition of many fish and crustacean species. As the consumers’ demand for aquaculture products is growing rapidly, the demand for live feeds in larviculture is increasing as well. To satisfy the growing demand, research has taken steps to develop new innovative live feeds. Several studies focused on nematodes as a potential food source for larvae. Production methods, culture media, harvest, and enrichment procedures for nematodes presented in these studies are reviewed here. Many studies fed nematodes to different species of fish and crustaceans to test applicability in larval nutrition. The results of these feeding trials in terms of larval performance as well as ingestion and digestion of nematodes in the larvae’s gut are reviewed here as well. In addition, a summary of advantages and disadvantages of nematodes as live food and an outlook on future challenges of production and application of nematodes in larviculture are also presented.
	Citation:	Jens Brüggemann . Nematodes as Live Food in Larviculture – A Review. Journal of the World Aquaculture Society, Volume 43, Number 6 (December 2012), pp. 739-763, <http://ejournals.ebsco.com/direct.asp?ArticleID=48DEAE43EDB19754BF8D&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=48DEAE43EDB19754BF8D

One of my clients is a stickler for maintaining balance in the aquaria, not wanting to use medicines whenever possible. This is a valid approach from a biologist point of view and has a place in larger environments. Sometimes however, in an artificial aquarium system where there is a higher than normal stocking densities, a veterinary approach may be more appropriate. But the balanced approach is particularly important when dealing with bacteria, whether you’re using antibiotics, or water disinfection tools.

This article details the effects of UV on beneficial bacteria.

Aquaculture Research
Volume 44, Number 2 (January 2013)
	Effect of ultraviolet (UV) radiation on the abundance and respiration rates of probiotic bacteria.
	Authors:	M. Angélica Garrido-Pereira, André Luiz Braga, Andréa Ferretto da Rocha, Luís André Sampaio, Paulo César Abreu
	Author Affiliations:	no affiliations available
	Source:	Aquaculture Research, Volume 44, Number 2 (January 2013)
	Page Numbers:	261 – 267
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	Effects of ultraviolet radiation (UV) on probiotic bacteria (Bacillus subtilisand B. licheniformis) were tested in two experiments, with the following treatments: (i) UVtreatment – using fluorescent and UV-lamps and (ii) Control – CTRL, using fluorescent lamps. Bacterial abundance and respiration were evaluated every 24 h for 3 days for Experiment 1, and at 0, 6 and 24 h for Experiment 2. In the Experiment 1, total UVdose was 4 336.41 mW cm-2. UVtreatment presented small respiration rates only on day 3, while in the CTRLoxygen consumption was always high. On all days, the abundance of the Bacilliexposed to UVwas significantly smaller than that of the CTRL. The second experiment, with total UVdose of 1 445.47 mW cm-2, presented oxygen consumption in the UVtreatment only during the first 6 h. In the CTRL, oxygen consumption increased from the beginning due to the bigger abundance Bacillicells. Small coccus-shaped bacteria ocurred in the UVtreatment of both experiments. It may be concluded that exposure to UV, normally used for water disinfection, can inactivate probiotic bacteria.
	Citation:	M. Angélica Garrido-Pereira, André Luiz Braga, Andréa Ferretto da Rocha, Luís André Sampaio, Paulo César Abreu . Effect of ultraviolet (UV) radiation on the abundance and respiration rates of probiotic bacteria. Aquaculture Research, Volume 44, Number 2 (January 2013), pp. 261-267, <http://ejournals.ebsco.com/direct.asp?ArticleID=4B39AD4953156DF27216&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=4B39AD4953156DF27216

I’ve made numerous diagnoses of newly hatched fry dying from starvation despite been given access to plenty of Artemia. The main reason for this is the capsule/shell of the cysts cause gut blockage. So, it is very important to separate the Artemia from their capsules.  If this proves difficult, there are means of decapsulating the cysts prior to trying to hatch them (e.g. using chlorine).

But what if your Artemia are of poor quality, having poor hatch rates? This article is interesting because it demonstrates that unhatched, decapsulated cysts can still provide good nutritional value once the fry are big enough to take them.

Aquaculture Research
Volume 44, Number 2 (January 2013)
	Decapsulated Artemiacysts of different quality (high or low hatch-rate) as direct food for tench (Tinca tincaL.) larvae
	Authors:	Jesús D. Celada, Vanesa García, José M. Carral, María Sáez-Royuela, Rocío González, Álvaro González
	Author Affiliations:	no affiliations available
	Source:	Aquaculture Research, Volume 44, Number 2 (January 2013)
	Page Numbers:	167 – 175
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	Three 30-day experiments were conducted to evaluate decapsulated Artemiacysts with different quality (high or low hatch-rate) as food for tench (Tinca tincaL.) larvae from the onset of exogenous feeding. In experiment 1, three diets were tested: Artemianauplii-only or cysts-only for 30 days, and nauplii for the first 7 days and cysts thereafter. The cysts used had 86% hatching rate (high hatch-rate cysts). The same feeding treatments were replicated in experiment 2 but with low hatch-rate cysts (10% hatching rate). In experiment 3, five diets were tested: high hatch-rate cysts only or low hatch-rate cysts only for 30 days, and nauplii for the first 7, 4 or 2 days and low hatch-rate cysts thereafter. In overall, survival was high, except with the low hatch-rate cysts only diet. Feeding tench larvae with cysts resulted in higher growth and lower FCRcompared to feeding with live nauplii only. High hatch-rate Artemiacysts are a suitable food from the onset of exogenous feeding and low hatch-rate cysts can be successfully used after 2–7 days feeding on nauplii.
	Citation:	Jesús D. Celada, Vanesa García, José M. Carral, María Sáez-Royuela, Rocío González, Álvaro González . Decapsulated Artemiacysts of different quality (high or low hatch-rate) as direct food for tench (Tinca tincaL.) larvae. Aquaculture Research, Volume 44, Number 2 (January 2013), pp. 167-175, <http://ejournals.ebsco.com/direct.asp?ArticleID=4B8993597532109BC927&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=4B8993597532109BC927

Read more here-
http://aquatichealth.net/node/69846

When working in Tasmania as a veterinary fish pathologist, the University of Tasmania were in the beginning stages of researching the striped trumpeter as an aquaculture species. They kept running into the issue of a parasitic infection that struck the larvae. These parasites seem to have an affinity for the nervous tissue, hence the scientific name “neuro” meaning “nerve”, and “phila” meaning “love”. The parasite seems to only infect the larvae within a certain age range, when their cartilage hasn’t fully ossified. So, to be able to bring up the fish past this age period could mean that we’re on the home run with making the culture of this species commercially viable.

During that time, only filtration seemed to be the option of getting around this issue. But this method is very costly and you wouldn’t be able to get the high volume of water exchange needed to maintain optimal water quality. Many other methods trialled led to infection by the parasites. This paper publishes data about using ultraviolet radiation as a way of nuking these bugs, to get the striped trumpeter larvae past this hurdle.

This finding has great transferability to other sectors including the treatment of ship ballast water in the prevention of pathogen or invasive organism transfer from port to port.

Journal of Fish Diseases
Volume 36, Number 1 (January 2013)
	Ultraviolet irradiation is an effective alternative to ozonation as a sea water treatment to prevent Kudoa neurophila (Myxozoa: Myxosporea) infection of striped trumpeter, Latris lineata (Forster)
	Authors:	J M Cobcroft, S C Battaglene
	Author Affiliations:	no affiliations available
	Source:	Journal of Fish Diseases, Volume 36, Number 1 (January 2013)
	Page Numbers:	57 – 65
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	Myxozoan parasites are known pathogens of cultured finfish. Kudoa neurophilan. comb. (Grossel, Dyková, Handlinger & Munday) has historically infected hatchery-produced striped trumpeter, Latris lineata (Forster in Bloch and Schneider), a candidate species for seacage aquaculture in Australia. We examined the efficacy of four water treatment methods to prevent K. neurophila infection in post-larval (paperfish) and juvenile striped trumpeter. Treatments included dose-controlled ultraviolet irradiation [hydro-optic disinfection (HOD)], ozone with conventional UV(ozone), mechanical filtration at 25 µm and then foam fractionation (primary filtration), and 50-µm-filtered sea water (control). In post-larvae (initially 10.3 ± 2.7 g, mean ± SD, 259 days post-hatching, dph), the infection prevalence (PCRtest) after 51 days was 93 ± 12% in the control, 100 ± 0% in primary filtration and 0 ± 0% in both ozone and HOD. Likewise, in juveniles (initially 114 ± 18 g, 428 dph), prevalence was 100 ± 0% in the control and primary filtration treatments with no infection detected in ozone and HOD. Concurrently, there was a 50–100% reduction in heterotrophic bacteria and 100% reduction in presumptive Vibriosp. in sea water HOD and ozone treatments. HOD with a dose of =44 mJcm-2UVwas as effective as ozonation at >700 mV ORPfor 10 min, in preventing K. neurophila infection.
	Citation:	J M Cobcroft, S C Battaglene . Ultraviolet irradiation is an effective alternative to ozonation as a sea water treatment to prevent Kudoa neurophila(Myxozoa: Myxosporea) infection of striped trumpeter, Latris lineata(Forster). Journal of Fish Diseases, Volume 36, Number 1 (January 2013), pp. 57-65, <http://ejournals.ebsco.com/direct.asp?ArticleID=472BA1B8E4754C97F1BD&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=472BA1B8E4754C97F1BD

Check it out here –

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