Fish Hiding

[FishMom23]

Hello! We just got our first fish tank for our daughter’s birthday and are wanting to do the best we can to care for them well. We have two young female molly fish in a 5 gallon tank and a nerite snail, and we’ve had them since Saturday. Saturday and Sunday the fish and snail were active, busy, eating happily, and exploring the tank, but today they have been hiding behind/next to their heater and won’t come out even to eat.

At first I thought perhaps our tank was too cold. I double checked the temperature in their tank at four different points, and it was 77.5 F everywhere I checked. Do you have any other thoughts on what might be wrong and/or what I can do? We had our water tested on Saturday at the aquarium store before we got fish, and they said it looked great, and we did intentionally go to an aquarium store rather than a general pet store so that they could advise us well on tank, fish, food etc. Today, though, they are closed for the New Year.

[Aiken Drum]

It doesnt sound like you cycled the tank before getting your fish (fishless cycle), and it also look like you know how to cycle a tank with fish in it. Your fish produce waste and in an uncycled tank waste builds up to toxic levels. Ill post something that explains the nitrogen cycle as well as a process to do a fish in cycle.

Change 50% of the water as soom and you are able and until you are able to test your own water change 50% of the water everyday. This will help prevent your water getting toxic without you knowing about it.

Do not go back to that fish store for advice.

1. They allowed you to buy fish without ensuring you know how to safely keep them and without explaining the nitrogen cycle to you. All their testing did was confirm your tap water was free of harmful contamination, and this does nothing to ensure your system will remain that way once you add fish into the system.
2. They allowed you to buy fish that are unsuitable for your tank size. A 5g tank simply isnt big enough to keep 2 mollys healthy and happy. You should either upgrade the tank to 10g (20g would be better), or return the mollys and get a fish more suited to 5g, like a single betta.

Fish stores are there to sell you stuff. They either dont care or dont understand how to keep fish. If they sell you something unsuitable, they get to sell medication if your fish get sick. If your fish dies they get to sell you more fish. If they sell you fish that will outgrow your tank they get to sell you a bigger tank. Big lesson learnt early in your fish keeping hobby.

[Aiken Drum]

The nitrogen cycle is the natural processes that go on in your tank that convert ammonia into less harmful substances.

Ammonia gets into your tank through various pathways. Fish waste, decaying uneaten food, and dead, decaying plants are common ammonia sources in an aquarium. Its also possible your tap water is an ammonia source. Chloramine is a common water treatment and when treated with most water conditioners the bond in the chloramine breaks and releases ammonia into the water.

Ammonia can be toxic to fish, depending on how much there is, and what the pH and temperature of your tank water is.

The first stage of the nitrogen cycle is the removal of ammonia. If you have real plants in your tank some of this ammonia will be absorbed as part of their natural growth. Generally though ammonia is consumed by denitrifying bacteria that lives mostly on your filter media. These bacteria consume the ammonia and produce nitrite. Unfortunately nitrite is pretty much as toxic to fish as ammonia.

The second stage of the nitrogen cycle is the removal of nitrite. A different denitrifying bacteria will consume the nitrite and produce nitrate. Nitrate is much less harmful than ammonia and nitrite, and for most aquariums the nitrogen cycle ends there. Excess nitrate is removed through your regular water changes.

A further stage of the nitrogen cycle can also happen, but its difficult to remove all the nitrate from a typical freshwater aquarium. Plants will absorb some nitrate in a similar manner to how it absorbs ammonia to grow. There are also nitrifying bacteria that consumes nitrate and gives off nitrogen gas which will simply offgas from your aquarium. This nitrifying bacteria is difficult to grow in freshwater aquarium.

“Cycling” a tank is the process you go through to grow denitrifying bacteria in your aquarium to consume ammonia and nitrite. You are said to be “cycled” when you have enough bacteria to consume all the ammonia and nitrite that your tank produces and turns all of it into nitrate. If you test the water of a cycled tank you should see 0 ammonia and nitrite and some nitrate.

[Aiken Drum]

To cycle a tank you need to grow denitrifying bacteria to consume ammonia and nitrite that your tank produces. The bacteria needs an ammonia source to grow colonies sufficient in size to consume all the ammonia and resultant nitrite and turn it into nitrate which typically you remove through your regular water changes.

A fish in cycle uses fish waste as an ammonia source and regular water changes are undertaken to ensure that water parameters are maintained at relatively non toxic levels.

Set up your tank. Make sure everything is running smoothly. Make sure you have used a water conditioner product with any tap water you have put in your tank. Seachem Prime is a water conditioner that will also detoxify some ammonia for a day or two, so is a good choice for a water conditioner while cycling a tank with fish.

You should have a test kit. Preferably a liquid test kit. It should test for ammonia, nitrite, and nitrate.

In ideal circumstances you should be starting a fishless cycle with a low bioload (number of fish). 1 small fish per 10 gallons/40 litres is a good number of fish, but this can be tweaked a little for fish that are social and don’t do well on their own. Ideally a hardy type of fish. You may have fully stocked (or overstocked) your tank before you knew about cycling. In these circumstances, if its not possible to return fish, you will have to make the best of it.

If you haven’t already done so, add your fish. Acclimate them to the water in your tank before doing so.

Feed lightly to start with. Daily as much as is eaten in 2 minutes, or as much as is eaten in 3 minutes every 2 days. You can increase to full feedings if you are confident your parameters aren’t getting too elevated too quickly and water changes don’t become a daily thing.

Start to regularly test the water for ammonia and nitrite. At least daily. Depending on your bioload you could start to see ammonia quite quickly. Nitrite will likely take a little longer to appear.

Your target should be to keep ammonia + nitrite combined no higher than 0.5ppm by changing water whenever your water parameters exceed this target. 0.5ppm combined is a level of waste that is sufficient for your cycle to establish but relatively safe for your fish.

If you see 0.5ppm ammonia and 0.0ppm nitrite (0.5ppm combined) then leave things be. If you see 0.5ppm ammonia and 0.25ppm nitrite (0.75ppm combined) then change 1/3 of the water. If you see 0.25ppm ammonia and 0.75ppm nitrite (1.0ppm combined) then change 1/2 the water. If water parameters get worse than these levels it may require multiple daily 50% water changes to maintain safe water conditions. This is more likely to happen with a fully stocked tank.

Remember to add water conditioner whenever you put tap water in the tank.

Over time the frequency of water changes and amount you need to change to maintain your ammonia + nitrite combined target will reduce. You can also start testing for nitrate and should see this rising. If you are finding the ammonia and nitrite in your tests are consistently low, and you aren’t already fully stocked, you can add a few more fish. It may take a few weeks to get to this point.

Once you add a few more fish, continue to regularly test the water and continue to change water if you exceed the 0.5ppm combined ammonia + nitrite target. With added bioload the frequency of water changes and amount you need to change may increase again until your cycle has caught up. Again once you are consistently seeing low ammonia and nitrite you can add some more fish. Rinse and repeat with testing, water changes, and adding fish when safe to do so until you are fully stocked.

You can then cut back on water changes to control nitrate only. Typically you want to keep nitrate no higher than 40ppm, but I would recommend changing some water every 2 weeks even if your water test says you don’t need to.

A fish in cycle from an empty tank to fully stocked can take several months.

A good way to speed up this process would be to put a small amount of filter media from an established filter into your filter, or get a sponge from an established filter and squeeze it into your tank water. Perhaps you have a friend who keeps fish who could let you have some? This will seed your filter with the bacteria you are trying to grow and speed up the process.

Another option is bottled bacteria like Dr Tims One + Only or Tetra Safestart. These products wont instantly cycle a tank as they claim but in a similar manner to adding established filter media they can seed your filter with the bacteria you are trying to grow to establish your cycle. These products are hit and miss as to whether they work at all, but are an option if established filter media isnt obtainable and may speed up the process from several months to several weeks.

[Colin_T]

Hi and welcome to the forum

Can you post a picture of the entire tank?

Reduce the feeding to 2-3 times a week until the filter has established, then you can feed once a day. Don't worry, the fish won't starve. Unlike mammals and birds that use most of the food they eat to keep warm, most fish take their body temperature from the surrounding water. This means any food they eat is used for moving and growth.

Do big daily water changes to help keep ammonia levels down while the filter develops. In a month or so when the filter has established, you can do a water change once a week.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Do you have a picture on the back of the tank?
You can buy aquarium backings from any pet shop, online, or use coloured card or a plastic bin liner. Just tape them to the outside on the back of the tank. The backing will help the fish feel more secure.

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TURNING LIGHTS ON AND OFF
Stress from tank lights coming on when the room is dark can be an issue. Fish don't have eyelids and don't tolerate going from complete dark to bright light (or vice versa) instantly.

In the morning open the curtains or turn the room light on at least 30 minutes (or more) before turning the tank light on. This will reduce the stress on the fish and they won't go from a dark tank to a bright tank instantly.

At night turn the room light on and then turn the tank light off. Wait at least 30 minutes (or more) before turning the room light out. This allows the fish to settle down for the night instead of going from a brightly lit tank to complete darkness instantly.

Try to have the lights on at the same time each day. Use a timer if possible.

If you don't have any live plants in the tank, you only need the light on for a couple of hours in the evening to view the fish.

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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).

Depending on what the GH of your water is, will determine what fish you should keep.

Angelfish, discus, most tetras, most barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.

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.

If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.

[FishMom23]

Thank you so much to both of you for your replies! I did a partial water change and significantly decreased the amount of time the lights were on each day, and our fish have come out of hiding. I’m now working on cycling the tank as recommended and have reduced the fishes’ feedings until things are regulated.

I don’t have a good way to share pictures of our tank, but it’s the Pisces Nano Bowfront, and our initial water was prepared water we bought from the fish store. I had a supply of that that I was using for water changes until today when I started using our tap water. We have been using Seachem stability as recommended by the aquarium store, and we also have the Seachem Neutral Regulator to use as a water conditioner because the natural pH of our tap water is quite high.

My girls are already quite attached to the fish, so I’d rather not return them to the store. I’m going to work on getting them a bigger tank to transfer to instead and putting something smaller in this one, but it might take a couple months. I’m hoping to keep the mollies as healthy and happy as possible in the little tank in the meantime and, once I get it, will do a fishless cycle on the bigger tank before transferring them.

[Colin_T]

When you get a bigger tank, you won't have to do a fishless cycle. You can simply transfer half of the filter media onto the new tank's filter and move the fish straight across.

If you have sponge in the filter, you can cut it in half. Or you can add more sponge to the filter so you just take one sponge for the new tank and leave the other sponge where it is.