Advice About Fish Tank?

[bekyfish]

Hello there,

I'm reasonably new to keeping tropical fish - I had goldfish for a long time but they died when a friend overfed them while I was away.

I started out with three guppies in a 30l tank. I had them for a month and the tank seemed to be running fine, so I introduced a silver shark. A few days later, I woke up one morning to find one of the guppies dead on the bottom of the tank, with a big chunk out of it, and the shark was feeding on it. I have read that silver sharks do not prey on their tankmates, so I'm not sure if the guppy died before the shark started feeding on it, or if the shark actually killed it by eating it. A few days later, I went away for the weekend and my housemate fed the fish (this time I'd given strict instructions not to overfeed). When I came back, another guppy was gone. But this time there was no body so I can only assume the shark ate the whole thing. Still don't know what was the actual cause.

So now I'm left with one guppy and one silver shark. They seem to be getting on fine as tankmates, its been over a month since the others died so I assume the shark doesn't want to eat his buddy. I will restock the tank at some point but first I want to make sure everything is fine.

Now, my main question is about the tank itself. It seems to have brown spots of mold growing on the side of the tank, I've tried researching it and I'm not sure if its brown algae or mold. There are lots of small circles or spots that look like mould. I took a couple of pictures to help someone identify it for me, but in the pictures you can only see a couple of spots. When you look closely though, there are quite a lot of the brown spots forming, its just really hard to get on a camera.

Hopefully someone can tell me what it might be and what I need to do to make sure my tank is healthy.

Thank you!

Beky

 

[Littlemonkey]

Welcome Beky,

I've never heard of a Bala shark eating other fish, but as you will learn the 30 litre is way too small for the Bala Shark. Do you wish to up-grade soon, if not see if you can return the Bala or rehome. How long has your tank been running, did you cycle first before adding fish. If you can give us as much information as you can there will be lots of people who can help you. Good Luck.

 

[bekyfish]

Welcome Beky,

I've never heard of a Bala shark eating other fish, but as you will learn the 30 litre is way too small for the Bala Shark. Do you wish to up-grade soon, if not see if you can return the Bala or rehome. How long has your tank been running, did you cycle first before adding fish. If you can give us as much information as you can there will be lots of people who can help you. Good Luck.

My tank has been running for about two months. I didn't cycle my tank because I'd never heard about it. I had the tank running with no fish and full of conditioned water for about 7 days before I introduced the guppies, then I waited another few weeks before introducing Sharky. I didn't realise that the Bala sharks would grow huge - actually the staff at my favourite fish store told me it wouldn't grow that much, that he'd kept a silver shark for a really long time without it growing big. I know the staff in the shops can often be wrong but I was slightly surprised as they're usually very knowledgeable and helpful in that shop. *sigh*

The remaining two fish seem healthy now though, although I'm worried about the "mould" stuff thats growing.

 

[Littlemonkey]

Welcome Beky,

I've never heard of a Bala shark eating other fish, but as you will learn the 30 litre is way too small for the Bala Shark. Do you wish to up-grade soon, if not see if you can return the Bala or rehome. How long has your tank been running, did you cycle first before adding fish. If you can give us as much information as you can there will be lots of people who can help you. Good Luck.

My tank has been running for about two months. I didn't cycle my tank because I'd never heard about it. I had the tank running with no fish and full of conditioned water for about 7 days before I introduced the guppies, then I waited another few weeks before introducing Sharky. I didn't realise that the Bala sharks would grow huge - actually the staff at my favourite fish store told me it wouldn't grow that much, that he'd kept a silver shark for a really long time without it growing big. I know the staff in the shops can often be wrong but I was slightly surprised as they're usually very knowledgeable and helpful in that shop. *sigh*

The remaining two fish seem healthy now though, although I'm worried about the "mould" stuff thats growing.

They are allways helpfull when selling you fish, I have two in a 120 litre and I know they need to move to a bigger tank soon.
I cant tell by the picture what the Algae or mold is, Next time you do a water change clean the glass with a sponge (new, not used on anything else) or a scraper.

 

[arobinson1984]

Agree with littlemonkey here, you have been given bad advice from your fish store regarding the shark.

If you kept the silver shark in a 30L tank it wouldnt grow too big, it would stunt its growth.

The old myth of 'a fish only grows to the size of the tank it is in' is to a certain extent true but certainly isnt a good thing.

When a fish is kept in a tank that isnt big enough, it stunts the fishes growth which means the fish will stop growing. The thing most people dont realise is that the fishes internal organs will not stop growing so the fish ends up growing deformed and will have a slow painful death as they internal organs begin to grow too large for the fishes body frame. Stunting leads a fish to a painful and premature death.

A silver shark (aka bala shark) fully grown will reach around 12" long and as an adult need a minimum of a 6ft x 2ft x 2ft tank which is about 680L and they also should be kept in groups of 6+

Silver sharks kept in the right conditions can be easily expected to live 15+ years and quite often closer to 25 years.

Regarding the 'mould' which is more likely to be algae. What colour is it? How often do you have the tanks lights on for a day? If you clean with a sponge, make sure its a cheap sponge and not one thats comes with cleaning agents already soaked into the sponge as these will harm the fish

I highly recommend you:

1. Rehome sharky for the fishes sake
2. Have a good read of the threads that are linked in my signature regarding cycling, you are probably still in a fish-in situation.
3. Get a good liquid based test kit such as the API freshwater master kit. You cant rely on a lfs to test water, you need to be able to do it yourself as and when required.

Andy

 

[waterdrop]

Agree with the above advice, plus is would be good for us to review your gravel-clean-water-change technique and frequency at the same time as we review the status of your water test results once you get the kit.

~~waterdrop~~