Is there such a thing as too much space for a fish?

Jells90

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Hello, I'm new here and have been researching keeping tropical fish as I would like to get into the hobby. I know there is a minimum amount of space for fish but is there such a thing as too much space? I ask because someone is giving me a 90L tank for free which is much bigger than I would have bought but I don't feel confident in filling it with lots of fish and wanted to start off slowly with just a few tetras or guppy. Thanks 👍
 
You'll be fine with a bigger tank than the fish require.
Be sure to cycle your tank before adding fish. Read up on cycling in our cycling guide. I recommend the fishless cycle method.
 
Hello, I'm new here and have been researching keeping tropical fish as I would like to get into the hobby. I know there is a minimum amount of space for fish but is there such a thing as too much space? I ask because someone is giving me a 90L tank for free which is much bigger than I would have bought but I don't feel confident in filling it with lots of fish and wanted to start off slowly with just a few tetras or guppy. Thanks 👍
hello! when I upgraded my tank (57 or so L) to a 283 L tank, I only had around 5 fish, which were livebearers.
For guppies, large tanks are totally fine, and a 90L will be pretty active with just 3 or 4 of them.
however for tetras you need more than a "few", I usually get 8 and then 4 more later which is 12 in total.

I would just start with some guppies, they are small, delicate and lively.
 
You should buy a test kit for ammonia, ph, nitrite and nitrate. You will need this to cycle your tank properly.
You need to know your water hardness to figure out which fish will thrive in your water. Livebearers do best in harder water. Tetras and barbs etc do best in softer water.
 
Some fish must have soft water, some must have hard water and others do well in 'middling' water. It is best to choose fish which need similar water to our tap water.
For hardness - what we call GH - look on your water company's website. Your location is Devon, are you with South West Water? If that's the right company, enter your postcode here https://www.southwestwater.co.uk/services/your-water/postcode-search and tell us the number for German degrees in the box on the right of the page.
 
Hello 👋🏻

No such thing as too much space 😁 just make sure there's lots of live plants to make things feel more natural and make your fish feel safe. Great advice above, shout if you need more help 👍🏻
 
Welcome to here.
Once you know your waters GH tell us on here and we can make some recommendations on fish that suit your tanks dimensions.
Large fish or too many in a tank of your size won’t look good and result in their early deaths.Some fish need a minimum certain number around them to feel secure which helps them come out into the open. Otherwise they’ll hide away at the back of your tank and you’ll end up wondering why you ever bothered.
Have fun.
 
Some fish must have soft water, some must have hard water and others do well in 'middling' water. It is best to choose fish which need similar water to our tap water.
For hardness - what we call GH - look on your water company's website. Your location is Devon, are you with South West Water? If that's the right company, enter your postcode here https://www.southwestwater.co.uk/services/your-water/postcode-search and tell us the number for German degrees in the box on the right of the page.
Thanks for the information - I put in my postcode -
.

Hardness Information: Total Hardness level of 90 mg/l Ca​

Your water is classified as Hard
  • 225 parts per million
  • 16 Clarke degrees
  • 23 French degrees
  • 13 German degrees
 
Welcome to here.
Once you know your waters GH tell us on here and we can make some recommendations on fish that suit your tanks dimensions.
Large fish or too many in a tank of your size won’t look good and result in their early deaths.Some fish need a minimum certain number around them to feel secure which helps them come out into the open. Otherwise they’ll hide away at the back of your tank and you’ll end up wondering why you ever bothered.
Have fun.
.

Hardness Information: Total Hardness level of 90 mg/l Ca​

Your water is classified as Hard
  • 225 parts per million
  • 16 Clarke degrees
  • 23 French degrees
  • 13 German degrees
 
hello! when I upgraded my tank (57 or so L) to a 283 L tank, I only had around 5 fish, which were livebearers.
For guppies, large tanks are totally fine, and a 90L will be pretty active with just 3 or 4 of them.
however for tetras you need more than a "few", I usually get 8 and then 4 more later which is 12 in total.

I would just start with some guppies, they are small, delicate and lively.
Thanks for your reply - can I ask, any reason you would get 8 and then 4 later rather than 12 at once?
 
That is hard water but not 'very hard' - fish keeping uses 2 units, german degrees - also called dH - and ppm (part per million).
Fish profiles will use one or other of those units so make a note of 13 dH and 225 ppm.

Guppies will be fine in your water but it's too hard for the majority of tetras. Platies and endlers would also be OK in your tank, but 90 litres is a bit small for mollies and swordtails. Other fish like the smaller rainbowfish would also be ideal. Look at Pseudomugils for ideas.
The best site for fish research is Seriously Fish https://www.seriouslyfish.com/knowledge-base/ This is a site written by experts.


Re Sgooosh's adding 8 then another 4, it is better to add a whole shoal at the same time. If you do a fishless cycle, it is safe to add a lot of fish at the same time once the cycle has finished. You'll find the method in Fishmanic's link is post #2.
 
My advice is to go look at local water bodies. Chances are, even in thriving ecosystems, that you won't see a lot of fish .

Most fish are social animals, and may not like living as individuals. They may need to be in groups. Others may need different types of hiding places or shelters. But if they have what they need, you can have one small group in a 120 gallon.

There are no rules for fish. It goes species by species. We have the rules - most people hate an empty looking tank.
 

Is there such a thing as too much space for a fish?​


I don’t think that’s a valid question for a tiny 90 litre tank. Compare it to a river or lake.
 
I can give you another view on this. If you are limiting your question to the normal average community type tanks, then likely you can never go too big in terms of it being a healthier tank. However, If you breed fish or you have fish that breed and their babies survive, you will eventually need to catch them and rehome them (sell, trade or give away).

And then space matters. I can guarantee you that catching a tetra in a 100 gal. tank is a lot harder than catching one in a 50 gal. tank. And this is even more true when there is a lot of decor or heavy planting. And it is not only breeding which many necessitate catching fish, illness can also make this necessary. If you need to catch a sick or injured fish so you can move it to a Hospital tank to be treated, the same consideration applies.

I can tell you that in my very first tank, a 45 gal. which ultimately was also well planted, I had been sold flying foxes when I was trying to purchase Siamese Algae Eaters. So the Foxes had to go. I had to maake a bottle trap to catch them. However one refused to be trapped. It took me many months before i got it. And then it was dumb luck. I looked into the tank one day and saw that Fox inside the cave I had for plecos. So I grabbed a net, slipped it over the cave mouth and caught the fish.
 

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