Disease identification help

[PerryLaw02]

Hey there! I have this tank with guppies and a few Cardinal Tetras (shown above). Just recently, some of the guppies (mostly female) were dying (showing signs of fin decay), and I have no idea how to fix that (I researched online with no good results). In this post, I would like to focus on one female guppy that showed really unusual signs before dying. Pictures will be shown below:

As you can see, the mouth part looked like it was "rotten" (or torn), and there was a hole just behind the mouth. I was horrified and worried to see this, but I have no idea wether it was aggressive fish bullying, or some disease. Please help identify, and thanks for help.
P.S. If you can, try giving suggestions on how I should improve my tank. I hope to improve he living environment of the fish.

Best regards,
PerryLaw02

 

[fluttermoth]

How big is your tank and how many fish do you have? Have you tested the water at all? Is your water hard or soft? Why don't you have any substrate (sand or gravel) in the tank?

Sorry for all the questions, but most fish disease is caused by environmental issues, so we're unlikely to be able to work out what might be going on without the extra information.

 

[PerryLaw02]

Thanks for helping. I'll answer your questions.
1. My tank is 49cm X 30cm X 30cm, and water level is 23cm
2. I have lost track of how many fish are there, but it should be around 30 guppies, 9 Cardinal tetras and a few 1-week old fry.
2. Please explain what you mean by testing water. Also, how?
3. I have no idea wether the water is hard or soft, but it is basically non-processed tap water.
4. We didn't put substrate because my family members thought it would be difficult to clean the tank with substrate. We were also worried about the fish consuming the substrate.
Sorry if my answers seem silly, but I am quite new to this. Thanks for helping!

 

[Essjay]

Point 2. We test tank water for ammonia, nitrite, nitrate and pH using test kits. Some people use strip testers - though most don't do ammonia so you have to get a separate one for that - while others use liquid reagent testers with test tubes. These can be bought from fish shops and Amazon/Ebay.
They are important because both ammonia and nitrite are toxic to fish at low levels. They should always be zero in a tank. If they are not zero they can harm the fish. Nitrate is only toxic at higher levels, but as it is constantly made in the tank from fish waste we need to remove it by doing water changes.

Point 3. Look on your water supplier's website. Somewhere on there they should give the hardness. We need both the number and the units as they could use any one of about half a dozen units.
Hardness is important because fish have evolved to live at a particular hardness. They suffer if they are put into water of a different hardness. You have soft water fish (cardinals) and hard water fish (guppies) so one or other will not be happy.


The measurements you give make the volume 34 litres (9 US gallons). You have rather a lot of fish in that small volume. It would be fully stocked with just the cardinals, I'm afraid. And with that many female guppies, there will soon be an awful lot more guppies as all the females will have fry every month.
All those fish will be causing problems with your water quality; you need to cut down on the number of fish. Once we know if you have hard or soft water we'll be able to help you with that.

 

[PerryLaw02]

Thanks for your help. I appreciate it! I will purchase a kit when I can.
Oh by the way, does the number of fish in a tank relate to the size of them? My guppy females (which were of course larger) were around 2cm in length, so I thought they would go well in the tank.
If it really does matter, I will try to find a way. As always, thanks!

 

[Essjay]

Stocking a tank should always be based on the adult size of the fish; the fish in shops are juveniles which still have a lot of growing to do. Female guppies should grow to something like 6 cm with males a bit smaller.

A somewhat outdated guide to stocking is 1 inch of fish per American gallon, which means fish that up to a total of 9 inches/(23 cm) in your tank. Your 30 guppies give 180 cm of fish without even thinking about the cardinals.


But besides being overstocked you also have fish with different needs so one species will not be happy. Do you have soft water or hard water? Cardinals need soft, guppies need hard.

 

[PerryLaw02]

Thanks for your help. I have already ordered a kit and now waiting for it. However, I still have a few questions and problems.

1. I got both cardinals and guppies because I asked the person selling fish and he said both can be kept in the same conidion. I suppose I got scammed as your reply stated that Cardinals need soft water, and guppies need hard.
2. In these few days, I am still trying to look up the water type of my water supplier, but from observations (the guppies are still getting sick with some even dying), I guess the water is soft.
3. When I bought my guppies, the salseman said that these guppies have already reached sexual maturity (and that's how I got my fry). Does that really mean that it's already around at it's maximum size?
4. Now that I got around 15-20 guppy fry, I had to buy a smaller tank (I got one that hung on the edge of the larger tank) to avoid the small fry being "scared" or being mistaken as food. Since I already have a plant in my tank, do I just let the fry hide themselves, or use the tank? If so, is 10cm X 10cm X 10cm large enough?

Thanks very much for your assistance and advice.

 

[Essjay]

The first lesson in fishkeeping is don't believe anything a shop tells you till you've researched it for yourself. Too many shop workers are only interested in making a sale and they don't know, or don't care about providing correct information.


Which country are you in, and if it's the UK what is the name of your water company? I'll have a look in their website and see what I can find. That's cheaper than buying a test kit.

Female livebearers can give birth when quite young, not yet fully grown. These "teenage pregnancies" just produce fewer fry than mature females.

Those boxes that hang on the side don't allow the fry to grow properly as they are too small. It is better to leave the fry in the main tank. Some will get eaten, but some will survive if they have somewhere to hide.
And don't forget that each female will give birth every month. Then the female fry that survive will also start having babies. If you try to save every fry, you'll soon run out of tank space for them.

 

[PerryLaw02]

Thanks all for help. I searched + tested the water and concluded that it's soft, so I sold my guppies and the fry (sad to see them go, but they don't belong here). So I suppose the problem is solved. Case closed.
Anyways, with the Cardinals, are the 9 of them enough for the tank or should I get more? If yes, how many more? Thanks once again (I know this is irrelevant, but just asking)

 

[SeanTrollope]

hi there and welcome. i must just state that i think your are making the correct choices over here.

may i also add that a substrate would not have any negative affects and the fish will benefit from it. also it allows for bacteria to grow. this helps reduce the chance of disease.

 

[Essjay]

I think I would stay at 9 cardinals for now. If you test the water and find that nitrate hardly goes up between one water change and the next, maybe get 2 more.

I agree with Sean. A tank looks better with a substrate whether it is sand or gravel. We need more micro-organisms than just the ones that 'eat' ammonia and nitrite to keep a tank healthy, and a lot of these micro-organisms live in a substrate. Since you have no live plants that need to be rooted in a substrate, you could go for any gravel or sand of your choice, though avoid anything white and remember that day-glo gravel detracts from the fish. Gravel or sand will need thorough washing to get rid of dust - put some in a bucket, run water in stirring the gravel/sand, pour the dirty water away and repeat till the water is clear, then do the next batch.

 

[SeanTrollope]

yes i agree.

the reason we try and stay away from lighter colored gravel is firstly it is relatively unnatural as most natural substrates are brown or grey, secondly the darker your substrate the more your fish will stand out against it, essentially showing the fish off which is the main part if a fish tank.