Fish dying at a rate of 1 per week

[breeks]

Hi, my daughter has a smallish (70l) aquarium with a mix of guppies, mollies and platy. Total was 9 fish. I change the water once a week approx 70% water change, replace filter media monthly and test weekly using a decent testing kit. Over the past month she’s lost 1 fish per week - both mollies died within a week of each other kind of sinking to the bottom of the tank and floundering around for a while before dying. A ballon guppy was floating on the top of the tank last week, and yesterday a guppy died and (we think) has been eaten by his tankmates. As we‘re amateurs at this hobby we’re struggling to work out what the problem.

Water always tests healthy for ammonia, nitrate and nitrite. she feeds fish every other day - no use of chemicals in her room (scented candles, air freshener etc…). Water at 24 Celsius. Don’t use additives other than water treatment at point of water change. Any help would be much appreciated!

 

[Colin_T]

Pictures of the tank and fish?

How long has the tank been set up for?

What sort of filter is on the tank?
If you replace the filter media/ materials, you get rid of the beneficial filter bacteria and can have ammonia or nitrite problems. It is better to clean the media in a bucket of tank water once a month and then re-use the media. Tip the bucket of dirty water on the lawn.

If the media starts to break down, you can replace it with some sponge. Find a filter sponge for a different brand of filter and use a pair of scissors to the cut the sponge so it fits in the filter. Try to do this at least a month before you discard any of the original media.

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What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?

This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.

 

[breeks]

Hi - thanks for getting back.

Will get some decent photos posted of fish and tank and post them up.

Tank has been running since December 2021 - started with 2 x Platys (1 of which survives) and then in order added 5 small Guppies (4 surviving), 2 Mollies (both dead) and 2 Balloon Guppies (1 surviving).

Filter is a hang on back model that came with the tank - it's an Interpet CF2. The parts I change regularly are the filter cartidge (sponge) and there's an algaway pad. I don't touch the stone like material that sits in a bag in the filter.

Hardness data from my water supplier is here :

Calcium mg Ca/l = 12.75
Magnesium mg Mg/l = 2.71
Hardness as mg/l CaCO3 = 42.95
Hardness Level = Soft

PH = 7.5 (or thereabouts)

 

[AmyKieran]

Hi - thanks for getting back.

Will get some decent photos posted of fish and tank and post them up.

Tank has been running since December 2021 - started with 2 x Platys (1 of which survives) and then in order added 5 small Guppies (4 surviving), 2 Mollies (both dead) and 2 Balloon Guppies (1 surviving).

Filter is a hang on back model that came with the tank - it's an Interpet CF2. The parts I change regularly are the filter cartidge (sponge) and there's an algaway pad. I don't touch the stone like material that sits in a bag in the filter.

Hardness data from my water supplier is here :

Calcium mg Ca/l = 12.75
Magnesium mg Mg/l = 2.71
Hardness as mg/l CaCO3 = 42.95
Hardness Level = Soft

PH = 7.5 (or thereabouts)

Yeah I think the problem here is the replacement of the sponge, you don’t need to replace the sponge basically ever. Just every couple of weeks to a month, take some tank water out and rinse the sponge in the tank water then put back in the filter. By replacing it, your removing all of the beneficial bacteria

 

[Deleted member 149562]

I have had Interpet CF2 (currently have a CF1 on my Betta cube)

The media....ceramic noodles (leave in their cage and rinse in old aquarium water to get rid of excess poo)....then a white floss cartridge with inbuilt carbon (using old aquarium water rub tween fingers and thumbs to get rid of excess poo but do not replace til it literally falls to bits in your hand - then tear some away from the old to sit with the new) and the algae pad (again rinse off in old aquarium water then put back in place)

There is no sponge in the CF unless it is something you have put in there to replace the original media. If using sponge, as @AmyKieran rightly said, just rinse well in old aquarium water to remove excess poo.

Never follow the instructions on the boxes and replace all media every month....not necessary and only stated cos then you go spend more money with the company concerned.

The CF series are actually very easy to use DIY media using far cheaper floss and pads....for example a 500g bag of floss lasts over a year with a CF2 and costs less than ten quid, same with the pads...you can get individual pads for algae, nitrate, carbon etc for under ten quid that will last at least a year.

 

[Deleted member 149562]

To give an idea of costs.

The CF2 has their three month media pack that retails for around £10 to £18 depending on where you buy it



If used correctly and NOT according to their instructions, the three month supply can last in excess of 6 to 8 months and often much longer than that depending on the stocking and waste production levels of your fish.

Alternatively you can buy bulk individual floss and pads to suit your fish species needs

For example...

Superfish Carbon Pad - Activated Carbon

Activated carbon filter media for all filters, just cut to size

www.pro-shrimp.co.uk

Superfish Ammonia Pad - Activated Carbon

Activated carbon filter media for all filters, just cut to size

www.pro-shrimp.co.uk

Superfish Phos Pad - Activated Carbon

Activated filter media for all filters, just cut to size

www.pro-shrimp.co.uk

Superfish Nitrate Pad - Activated Carbon

Activated carbon filter media for all filters, just cut to size

www.pro-shrimp.co.uk

Superfish White Filter Wool - Filter Fllece 500g

Synthetic filter wool fleece for aquarium filters

www.pro-shrimp.co.uk

The pads can be cut to size and will slide into the filter body very easily and just require rinsing during the water change......never rinse the media in tap water though, always use the water removed from the aquarium.

DIY media will save you alot of money...and fishkeeping is expensive enough already without spending oodles of money on the branded media that the brand tells you to change far too often so that they get even more money out of you.
(On the links above, ignore the reference to "carbon" in all except the actual carbon pad...a quirk of the links unfortunately)

 

[breeks]

Thanks everyone.....it's good to get a solution to focus on. Seems so obvious now it's pointed out....will follow your guidance on filter media and see how things go. Anything is better than an upset 10 year old after yet another fish has died!

 

[Deleted member 149562]

You say that you have soft water?

That is going to be a potentially serious issue with the Mollies, Platies and Guppies as they prefer and thrive better in harder water...Guppies can handle softer water sometimes but its not really advised tbh.

You may want to rethink the stocking of your aquarium...especially to avoid upsetting your child when finding dead fish periodically.

I would consider checking out sites such as Seriouslyfish that will give you good stocking that will not only suit your water but the aquarium size too.

 

[Colin_T]

I would stop using the algae pad and the carbon one. They are contradictive. Carbon removes chemicals from the water. The algae pad adds algicide to the water, which is probably removed by the carbon. Algicides are also bad for the fish and other aquarium inhabitants.

Keep the ceramic beads/ noodles and add a couple of sponges the next time you clean the filter. The ceramic beads should hold enough beneficial bacteria to keep the ammonia and nitrite level at 0ppm while the sponges grow their colonies.

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Your GH is too low for livebearers and might be a contributing factor.
You can add mineral salts to the water to increase the GH, KH & pH. Rift Lake water conditioners are normally used for African Rift Lake cichlids. But you can use them at half dose for livebearers and other fishes that like harder water (eg: rainbowfish).

If you use something like Rift Lake water conditioner, you need to make up the water at least 24 hours before using it. Fill a clean bucket with dechlorinated water and add some of the Rift Lake salts. Aerate the solution for 24 hours so all the minerals dissolve into the water. Then use that water to do water changes on the tank.

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Try not to buy balloon fishes. They are shorter in the body than their normal counterparts and have lots of internal problems due to their organs being squished up. As a general rule, balloon fishes live about half as long as regular shaped fishes.

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Are the fish eating well?
What does their poop look like?

 

[Deleted member 149562]

@Colin_T

The carbon cannot be easily parted from the insert on CF filters, it is encapsulated within the floss cartridge. The algae/phos pad can be left out though.

 

[AdoraBelle Dearheart]

@Colin_T

The carbon cannot be easily parted from the insert on CF filters, it is encapsulated within the floss cartridge. The algae/phos pad can be left out though.

But you could surely cut the pad part away from the frame, remove the carbon etc, and just attach any aquarium floss cut to size to the frame and slide into the filter, right?

 

[Deleted member 149562]

But you could surely cut the pad part away from the frame, remove the carbon etc, and just attach any aquarium floss cut to size to the frame and slide into the filter, right?

Its actually too tight on the frame to reuse that frame once the carbon grains are removed. You are better off ditching the entire thing and just gently slipping unframed floss or use a floss mat into the filter instead