How do you tell if freshwater fishes have parasite ?

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anewbie

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How do you tell if fishes have parasite; i've had all my current fishes for over a year but i'm concern about one aquarium - mostly paranoid. I'm of the mind don't treat unless you know there is an issue to treat and i don't know how to determine if there is a parasite running around making my fishes crazy or what have you.
 
How do you tell if fishes have parasite; i've had all my current fishes for over a year but i'm concern about one aquarium - mostly paranoid. I'm of the mind don't treat unless you know there is an issue to treat and i don't know how to determine if there is a parasite running around making my fishes crazy or what have you.
Hello anewbie. Unless, you have a degree in fish biology, there's no way for you to tell about this sort of thing. There are bacteria, viruses and other disease causing organisms that live in all tanks. A healthy fish that is fed a small amount of a variety of foods and lives in a tank that gets large, routine water changes is essentially resistant to these organisms. The problems come up when you miss a water change or two or three and this causes a breakdown in the fishes' immune system. I wouldn't fret over what you can't control and focus on what you can like changing a lot of tank water and doing it regularly. This will keep the tank water clear of most of the things that can make your fish sick.

10 Tanks (now 11)
 
Hello anewbie. There are bacteria, viruses and other disease causing organisms that live in all tanks. A healthy fish that is fed a small amount of a variety of foods and lives in a tank that gets large, routine water changes is essentially resistant to these organisms. The problems come up when you miss a water change or two or three and this causes a breakdown in the fishes' immune system. I wouldn't fret over what you can't control and focus on what you can like changing a lot of tank water and doing it regularly. This will keep the tank water clear of most of the things that can make your fish sick.

10 Tanks (now 11)
While you wrote a lot of useful generic information; none of it actually answers my questions. Is there a way to identify if a fish has internal parasites ?
 
While you wrote a lot of useful generic information; none of it actually answers my questions. Is there a way to identify if a fish has internal parasites ?
i have had guppies for a few years, and it is really apparent when they get parasites. they are lethargic, have stringy white poop, and they get thin and pale looking.
when one fish is like this, the whole tank may have it as well, so i like to feed medicated food to the whole tank
 
i have had guppies for a few years, and it is really apparent when they get parasites. they are lethargic, have stringy white poop, and they get thin and pale looking.
when one fish is like this, the whole tank may have it as well, so i like to feed medicated food to the whole tank
The only sympton is one old fish a bit thin (not pale) not stringy white poop visible and definitely not lethargic.
 
It's a generic question.


You either find a website or purchase a book on fish diseases. Using the information and the photos, you narrow your search, so that you can determine what the signs are of each parasite. You cross reference them with the symptoms in your fish that concern you.

Parasites are diverse creatures.

Asking online could get you an answer from someone who has studied fish parasites, or from a guy who got fish last week and already thinks he knows everything. Someone who has only ever seen nematodes will give different info from someone who has seen tapeworms. There's a point at which you need to go old school and do a little bit of research.
 
Diagnosing fish diseases and inefections including parasites is the biggest bugaboo of the hobby for the reasons above and more. Some folks are more scientific and they will have a microscope. They can examine scrapings from fish or their poop. Most of us cannot or do not do this. So we are left with two things we can do.

The first is to watch for a change in behavior of the fish. For example, it may stop eating or it may be flashing against things in the tank as if trying to srcape something off. It may not be pooping or not eating. These are all clues. The second thing to see are external signs. For example, ich shows up as salt crystals all over the fish. Gill flukes can cause the fish to keep its gill flap open. Poop may change in appearance. A fish may get bloated or start wasting away. Any and all of these things provide more clues. Things like fungus are apparent and white patches on a fish are also.

If we are lucky and somewhat skilled, we may be able to diagnose from the clues. More often we are lost. The problem is a lot of fish ailments may not manifest any symptoms or different problems may cause similar symptoms. And we may be faced with fish in trouble and even dying and we are uncertain as to why. At that stage we have reached what I call the "take your best shot" option. When there we know fish are dying and we do not know why with any certainty.

What we do know is that if we do nothing we can end up with no live fish at all. So at that stage we just make the best guess we can and medicate accordingly. It is the last best shot we have. The thinking is that it doesn't matter if the fish dies because we did nothing as opposed to having it die because we tried the wrong thing. Dead is dead, On the other hand, our best shot may work.

I hate to offer this because it is somewhat technical, but it may help https://edis.ifas.ufl.edu/entity/topic/fish_parasites
Click on Common Freshwater Fish Parasites series underneath SubTopics
 
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do you have a photo? their whole body structure will change
I could take a picture of the aquarium but there is nothing overt. I do have one zebra loach that has gotten skinny - it is either one i've had for 4 years or 2 years but the problem is they can get skinny as they age and die - the actual fishes are not showing anything to overt. I have one misformed angelfish that has developed open sores but it is not shaped correctly and is a runt so i'm towards this problem as being more genetic. The problem is that (for example the tank with the zebra loach) there are 20 loaches in that aquarium and only one has developed the skinny since the loach was purchased as an adult there is no way to guess the age - it could be 6 or 7 or 12 or 13 (if it is one i've had for 4 years then add in at least a year or two to reach adult size); However i'm not seeing tank wide issues just a fish here or there. Some of the paranoid is a 18 months ago i made a purchase from an 'unreliable' seller. In the tank with the loach i also have 16 serpae and 16 cherry barb and none of them show obvious issues 'cept some of the barbs a bit on the 'fat' side of things - none of hte serpae i would consider over weight - also most of the 'fat' barbs are females which might attribute to their more plump nature. Nothing is wide spread enough for my to find commonality.
 
If we are lucky and somewhat skilled, we may be able to diagnose from the clues. More often we are lost. The problem is a lot of fish ailments may not manifest any symptoms or different problems may cause similar symptoms. And we may be faced with fish in trouble and even dying and we are uncertain as to why. At that stage we have reached what I call the "take your best shot" option. When there we know fish are dying and we do not know why with any certainty.

What we do know is that if we do nothing we can end up with no live fish at all. So at that stage we just make the best guess we can and medicate accordingly. It is the last best shot we have. The thinking is that it doesn't matter if the fish dies because we did nothing as opposed to having it die because we tried the wrong thing. Dead is dead, On the other hand, our best shot may work.

I hate to offer this because it is somewhat technical, but it may help https://edis.ifas.ufl.edu/entity/topic/fish_parasites
Click on Common Freshwater Fish Parasites series underneath SubTopics
This is my problem - with in a single aquarium i'm not seeing enough commonality to give a hint that makes me confidence. Death rates are extremely slow - order of multiple months. In one 29 i have 16 keri blue and 10 cardinals and 2 runt angels - no one has died in 4 months but the angel as described above is off - i'm include to think it is runt/weak bacterial infection.
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aq 2: only one fish has died in the past 4 months - but it was an eques cory; it might have gotten stabbed by a L397 given the behavior but i could not find an obvious puncture mark or something damaged its control of nervous system (parasite?).

aq3: i mentioned the skinny zebra loach.
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Something feels off but it isn't frequent enough for me to identify commonality. They definitely don't have velvet, ick, worms large enough to see with the naked eye, gill fluke - yes a loach will flash once in a blue moon but this is common behavior (once in a blue moon is like once a month (and usually not the same loach and not very long - like a few seconds). One of my clown loaches is not growing and has red gills but i've had it for 10 months and it came that way so i'm assuming ammonia burn prior to purchase. The other 5 purchased with it have grown and more than double in size (i have 10 5 older 5 newer).
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I'm not sure - something 'feels' wrong but at the current rate of death i will see 1 to 3 fish die per aquarium per year. None of the my dithers have died in 2 years (ember tetra, cardinals, keri, serpae). Wouldn't parasite go after all fishes regardless of species ?
 
A mis-shapen angel with sores is a massive clue. I'm afraid to say that's usually Mycobacter marinum - fish tb. It's in an incurable, untreatable communicable disease that the fish builds cysts around (causing deformities) and that when it escapes the cyst, spreads rapidly.
It causes wasting, crooked spines, rectangular sores and premature death. If the sores are open, the bacteria is spreading.

Treatment? It survives bleach. In rare cases it can jump the species barrier and infect humans (me, once...) with skin lesions and there, it takes 6 months of an antibiotic cocktail to clear it. It's nasty.
 
A mis-shapen angel with sores is a massive clue. I'm afraid to say that's usually Mycobacter marinum - fish tb. It's in an incurable, untreatable communicable disease that the fish builds cysts around (causing deformities) and that when it escapes the cyst, spreads rapidly.
It causes wasting, crooked spines, rectangular sores and premature death. If the sores are open, the bacteria is spreading.

Treatment? It survives bleach. In rare cases it can jump the species barrier and infect humans (me, once...) with skin lesions and there, it takes 6 months of an antibiotic cocktail to clear it. It's nasty.
So i should remove it from the tank before it spreads to other fishes in the aquarium? How long would it take for me to know if other fishes have been infected ? This is a runt malformed angel so putting it down is not the end of the world.
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This was an aquarium with L204, L128 and some cardinals and one other runt angel (but no obvious issues other than being a runt).
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I'm not sure this was the issue - I want to note that in this aquarium with 16 keri, 8 cardinals, 2 angels 1 male apsito, 6 sterbai, 1 l 204 and 1 L128 and 3 small bn (1 - 1.5 inch) no fish has died in 2 years - the angles were added on Jul 19 2022 (8 months ago as dime size); the full size ones were thinned and removed - the 2 runts were left. The fish developed the 'open sores' approx 2-3 weeks ago - and it did not have spine issue but enlargment in other places. My quick skimming of the disease seems to describe it as opportunistic so my question is if no other fish shows signs for the next 2 months - am i safe or is there a latent issue?
 
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Runt angelfish can be from inbreeding and poor genetics, malnutrition, bullied by something, lack of good food, intestinal worms, or a number of other things.

Sores on fish can be from various species of bacteria (not just TB/ Mycobacteria species) and usually get into the fish after the fish is injured.

Lots of stuff on here I can't be bothered reading right now and you've probably already mentioned what I'm going to ask.

What species of fish have died?
What symptoms do the fish have?
Do fish die from the same symptoms in all the tanks?
How long has it been going on for?
I assume the water quality is good (0 ammonia, 0 nitrite, less than 20ppm nitrate, pH and GH is suitable for the species)?
 
Runt angelfish can be from inbreeding and poor genetics, malnutrition, bullied by something, lack of good food, intestinal worms, or a number of other things.

Sores on fish can be from various species of bacteria (not just TB/ Mycobacteria species) and usually get into the fish after the fish is injured.

Lots of stuff on here I can't be bothered reading right now and you've probably already mentioned what I'm going to ask.

What species of fish have died?
What symptoms do the fish have?
Do fish die from the same symptoms in all the tanks?
How long has it been going on for?
I assume the water quality is good (0 ammonia, 0 nitrite, less than 20ppm nitrate, pH and GH is suitable for the species)?
Some answers - i will try to organize the answer in question:
120 gallon: This aquarium had a disease out break when i added some cherry barbs in May 22; the barbs didn't die but nearly everything else did die ( i presume some pathogen that didn't impact them; one angel, 9 out of 10 zebra loach and 3 clown loaches lived along iwth the barbs - what died included 20 cardinals; 4 clown loaches; 5 angels ...); i treated the tank with a anti-bacteria cockatail recommended by someone and repopulated the aquarium in July. Since july no one has died 'cept the festum did catch one cherry barb. In this tank the only thing odd are 1 clown loach not growing and has red gills (they were red when purchased so i presume ammonia burn; and one zebra loach has developed the skinny - i've had it for either 2 years or 4 years - it is part of a group of 10 and it was an adult when purchased). This aquarium is over populated and nitrate is around 45 - in 45 to 60 days the stocking in this aquarium will be split between a 450 and 550 and nitrate should go to near 0. I also treated this aquarium with a uv filter which seemed to do more good than the cockatail i used.
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'black' 29: This aquarium has had the most oddity I put some sparkling gourami in this aquarium from the same seller as the barbs and since then a few fish now and hten died including the gourami. I treated this aquarium about 3 months ago with a cocktail and no one has died in 3 months but last week one of my eques could not longer swim correctly and died (so 1 death in 3 months) - there was not a wide spread obvious issue aquarium like the 120 but the kuhil loaches all died and showed signs of bacteria infection. The eques were full adults when purchased so no clue on age but they did not look like young adults - they looked at least several years old. Nitrate around 15
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'white 29': This aquarium: This aquarium has only had 2 deaths in the past 2 years - It has 10 cardinals 15 keri 2 runt angles and some young plecos i'm growing out. The keri were recent additions (nov 22); the cardinals had been in there for nearly 2 years. One of the keri developed the dizzies (if that make sense) so out of paranoid i put it down yesterday with the angel. The angel come from a breeder on ebay i've used before and I expect a few runts from him - i believe his fishes are heavily inbred and he sells large groups dime size (well 12 fishes in this group); the red sores (really only 1) was a new thing i've not seen before - he could have been picked or scraped himself on hard scape - no way to know but he had other deformities (not 'bent' spine) but normal runt 'deformities'). The nitrate level in this aquarium is around 15.
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40 B - 2 known deaths the past 3 years (1 male borelli and 1 kubotai but my female nijjensi is 4 years old and male nannacara is 4.5 years old - i expect the nannacara to die in hte next 6 months as it is showing some more serous old age signs - the female nijsseni is actually quite vibrant in behvior and looks but just raw age suggest she is near the end of her time. The nitrate in this aquarium is around 10; but it is heavily over run with baby pleco ranging in size from 1/4 inch to 2 inch. When i move in 45/60 days i will round them up and sep the male/female as enough is enough. This aquarium does have some kubotai rasbora that are over 3 years old so i suspect some of them will be dropping soon based on age. I'm not concern about diseases in this aquarium but if i do have some disease in the other aquarium i would be worry abuot something happening.
 
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If you post some pictures of the fish it might offer more information.

Fish losing weight over a period of time is usually intestinal worms and or gill flukes. Section 3 of the following link can take you through the steps of treating for intestinal worms. Treat all your tanks at the same time because if one fish has worms, they all have worms. Deworming the fish and treating them for gill flukes (worming medication does that too) will remove one possible cause of deaths.

Fish dying a short time after new fish are added to that tank usually die from an external bacterial or protozoan infection. New fish should always be quarantined for at least 2 (preferably 4) weeks before being added to an established tank to stop the introduction of diseases into the established tank.

It's preferable not to mix several species of dwarf cichlid in the same tank because they are territorial and quite often fight. Even if they don't rip each other apart like bigger cichlids do, they still stress each other out and that weakens their immune system and makes them more vulnerable to diseases and death.

If you have lots of fish in a tank, even babies, you need to do lots of big water changes and gravel clean the substrate. Fish like suckermouth catfish (bristlenose) produce huge amounts of waste that can encourage protozoan parasites to explode in population, and lack of big water changes and gravel cleaning can let the pathogens get out of control and start killing fish. Your fish might not have an external protozoan infection but if you are keeping lots of fish in a ank, you need to do big (75%) water changes and gravel clean the substrate at least several times a week. The filter should also be cleaned at least once a month. this helps to minimise the number of disease organisms in the water and reduces the chance of the fish getting sick and dying.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

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BASIC FIRST AID FOR FISH.
The following should be done if you ever lose a fish or the fish get sick.

Test the water for ammonia, nitrite, nitrate and pH.

Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.

Do a 75% water change and gravel clean the substrate every day for a week or until the problem is identified. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so any medication (if needed) will work more effectively on the fish.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.
 

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