The Fish Vet's Blog

Many fish breeders swear by feeding live or fresh foods to fish to condition them for breeding. This recently published scientific article finds evidence to support this long standing belief.

Aquaculture Research
Volume 43, Number 5 (April 2012)
	Examination of broodstock diet effects on egg production and egg quality in flame angelfish (Centropyge loriculus)
	Authors:	Chatham K Callan 1, Charles W Laidley 1, Ian P Forster1,2, Kenneth M Liu 1, Linda J Kling 3, Allen R Place 4
	Author Affiliations:	1: Finfish Program, The Oceanic Institute, Waimanalo, HI, USA 2: Center for Aquaculture and Environmental Research, Fisheries and Ocean Canada, West Vancouver, Canada 3: School of Marine Sciences, University of Maine, Orono, ME, USA 4: Columbus Center, Institute for Marine and Environmental Technology, University of Maryland Center of Environmental Science, Baltimore, MD, USA
	Source:	Aquaculture Research, Volume 43, Number 5 (April 2012)
	Page Numbers:	696 – 705
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	This study was conducted to determine the effects of broodstock diet on flame angelfish (Centropyge loriculus) reproduction and generate baseline spawning performance (mean fecundity, egg fertilization, egg viability) and egg biochemistry data for this species. Sixteen flame angelfish broodstock pairs were maintained on one of three formulated diets or a raw diet (consisting of squid, shrimp, fish eggs and algae) to determine the effect of diet composition on the fecundity, egg fertilization rates and egg viability over a 7-month period. Although all the diets supported similar mean spawn frequency and fecundity over the duration of the experiment, the mean fertilization rates and egg viability were significantly greater among pairs receiving the raw diet. Egg fatty acid composition was generally reflective of the maternal diet and similar to the values reported for other tropical species. In particular, dietary factors such as n-3 highly unsaturated fatty acid and ARA level (which were elevated in the raw diet and eggs from fish receiving that treatment) are correlated with egg quality and are therefore worthy of future investigation. Because of the ease of conditioning, adaptability to varied formulated diets and continuous, sustained reproductive output, flame angelfish are an excellent model for examining the factors affecting marine fish egg and larval quality.
	Citation:	Chatham K Callan, Charles W Laidley, Ian P Forster, Kenneth M Liu, Linda J Kling, Allen R Place . Examination of broodstock diet effects on egg production and egg quality in flame angelfish (Centropyge loriculus). Aquaculture Research, Volume 43, Number 5 (April 2012), pp. 696-705, <http://ejournals.ebsco.com/direct.asp?ArticleID=4EDBB8586FB70ADB920A&gt;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=4EDBB8586FB70ADB920A

Histopathological survey
of lesions and infections
affecting sick
ornamental fish in pet
shops in New South
Wales, Australia.
Wickins SC, et al. (2011).
Dis. Aquat. Organ., 94
(2):143-152.
Abstract
The objective of this
study was to describe the
frequency of the histopathological
lesions and categorize the evident infections
in sick ornamental fish from pet shops in New South
Wales, Australia. We examined 108 fish that had evidence
of morbidity or mortality, including 67 cyprinids,
25 osphronemids, 11 poeciliids, 4 characids and 1 cichlid,
sourced from 24 retail outlets.
Conditions frequently observed in the study population
included branchitis (62/86, 72.1%), visceral granulomas
(41/108, 38.0%), dermatitis (17/55, 30.9%),
wasting (31/108, 28.7%), and intestinal coccidiosis
(18/104, 17.4 %). Branchitis and dermatitis were usually
due to monogenean flukes, or flagellate or ciliate
protozoa. Intralesional Microsporidia (16/41, 39.0%),
Mycobacterium (7/41, 17.%), or Myxosporidia (5/41,
12.2%) were identified in the majority of fish with visceral
granulomas; however, special stains were critical
in their identification. The proportion of histologically
evident infections was remarkably high (77/108,
71.3%), and parasitic infections predominated.

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Check this one out, shared by my friend who’s into gadgets.

https://www.zazz.com.au/daily/thingy/5674

In Perth we are fairly lucky with our tap water that it already comes with ~70mg/L of KH (carbonate hardness also known as [the pH] buffering capacity of water). Sometimes a bit more, sometimes a bit less. Provided that we carry out regular aquarium maintenance, we ought not run into issues with pH becoming too acidic because this level of KH should buffer against this. But did you know that this KH will be consumed and decrease over time? When this happens, your pH can fluctuate wildly, causing stress to the fish. Depending on several factors, your pH could drop to as low as 4.5! Very nasty for many fish.

What are some clues that might lead you suspect this could be occurring? Those species intolerant of low pH will develop excess white opaque mucus over their bodies and around the edges of their gill covers. They would become lethargic and hold their fins clamped to their body. The base of Their fins, especially their pectoral and pelvic fins will become congested. Fish will appear disoriented and lose interest in food. You will start to lose fish.

A quick water test would reveal a very low pH. Then a quick KH test would point to the reason for the low pH.

What to do? You will need to act quickly and slowly at the same time. ????

Act quickly to obtain buffering salts. But act slowly in terms of gradually increasing the KH and pH so as not to create more stress in the fish. Speak with your veterinarian or local fish shop for advice on the best combination of buffers for your individual system.

What are common sequelae such a condition? Fish may succumb to secondary bacterial infection and so antibiotics may be indicated.

The bio-filter may be destroyed by the low pH and so you’ll need to treat your system as a “new tank” in terms of the nitrogen cycle.

Also a note of warning whenever you use antibiotics is that it will whack your bio filter around and so it is very important that you conduct daily water testing especially for levels of ammonia and nitrite. Feeding should be reduced while the biofilter re-establishes itself, water changes conducted as necessary and bacteria starter cultures may be indicated at the completion of treatment.

Make sure you get a good set of water test kits.

Very often fish keepers call on veterinarians because they are convinced that they need antibiotics for their sick fish…. after consulting doctor Google. What is the issue with this?

For one thing, antibiotics may not be indicated as the treatment for the condition. There are really very many reasons why fish get sick. Could it be water quality issues? Different parasitic conditions? Virus? Stress? Trauma? Cancer? Notice that GPs do not simply dish out antibiotics at every consultation?

Why not? This paper details a very pertinent reason. High levels of resistance have been reported to amoxicillin, penicillin, tetracycline and oxytetracycline. I concur with this from all the lab testing I have conducted. Where indicated, my first line antibiotic would not include these drugs.

;

;

Zoonotic bacteria, antimicrobial use and antimicrobial
resistance in ornamental fish: a systematic review
of the existing research and survey of aquaculture-
allied professionals
Weir M, A Rajic, L Dutil, N Cernicchiaro, FC Uhland, B
Mercier & N Tusevljak (2012). Epidemiology & Infection,
140 (2): 192 – 206.
Abstract
Using systematic review methodology, global research
reporting the frequency of zoonotic bacterial
pathogens, antimicrobial use (AMU) and antimicrobial
resistance (AMR) in ornamental fish, and human illness
due to exposure to ornamental fish, was examined. A
survey was performed to elicit opinions of aquacultureallied
personnel on the frequency of AMU and AMR in
ornamental fish.
The most commonly reported sporadic human infections
were associated with Mycobacterium marinum,
while Salmonella Paratyphi B var. Java was implicated
in all reported outbreaks. Aeromonas spp. were most
frequently investigated (n=10 studies) in 25 studies surveying
ornamental fish from various sources. High levels
of resistance were reported to amoxicillin, penicillin,
tetracycline and oxytetracycline, which was also in
agreement with the survey respondents’ views.
Studies on AMU were not found in our review. Survey
respondents reported frequent use of quinolones,
followed by tetracyclines, nitrofurans, and aminoglycosides.

Recommendations for future surveillance and
public education efforts are presented

Don’t stress trying to find the nearest veterinarian for your fish. We do house calls on weekends and weekday evenings.