How many fish for 85litre tank?

[ElizabethW]

I have a newly (fishless) cycled tank and wonder how many fish I can safely put in it.

Capacity: 85 litres
Water params: stable for the last week.
Ammonia - 0
Nitrites - 0
Nitrates - 20ppm
pH - 7.4
I'm not sure about the exact readings for hardness, as I've not tested, but the water company says it's a hard water area with calcium carbonate readings of 260ppm.

I've read a few places and it seems the best fish for me to get are guppies because they like hard water, but I can't really find any kind of reliable guide about how many I should get for a tank this size. I was also thinking of perhaps getting some shrimp. Are there any that are safe to have with guppies and like hard water? Any advice appreciated!

 

[DomH]

Start with 1 male and 3 females. And boom they will populate just feed them.


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[Mrscmurray]

I think most shrimp are fine with guppys as long as they have plenty of places to hide

 

[NickAu]

Guppies like most fish will eat shrimp babies.

 

[the_lock_man]

Start with 1 male and 3 females. And boom they will populate just feed them.

And therein lies the problem. They will overpopulate your tank very easily and very quickly. Each female can have 30 or so fry every 4-6 weeks, so with 3 females, that's 90 fry in a couple of months. You will find it difficult to move the fry on, most LFS won't take them. After 3 or 4 months, those 90 fry will be sexually mature. Let's assume that half of them are female. That's 45 x 30 fry per couple of months (to save you doing the maths, that's 1350 fry). I'm guessing that you probably don't have enough room for all those fish.

In any case, guppy females are very drab.

Probably best all round if you get all males.

I think most shrimp are fine with guppys as long as they have plenty of places to hide

Like Nick says, any fish will eat a shrimplet, but it's amazing how fast an adult shrimp can move with just those little legs to move with. I've always had trouble keeping crystal shrimp (the caridina spp.) in hard water, but red cherries (neocaridina heteropoda) bred like wildfire until I introduced my peacock gudgeon (they like a bit of live food....). Amano shrimp (caridina multidentata) were also no problem and would be big enough not to be considered food by guppies.

 

[ElizabethW]

And therein lies the problem. They will overpopulate your tank very easily and very quickly. Each female can have 30 or so fry every 4-6 weeks, so with 3 females, that's 90 fry in a couple of months. You will find it difficult to move the fry on, most LFS won't take them. After 3 or 4 months, those 90 fry will be sexually mature. Let's assume that half of them are female. That's 45 x 30 fry per couple of months (to save you doing the maths, that's 1350 fry). I'm guessing that you probably don't have enough room for all those fish.

In any case, guppy females are very drab.

Probably best all round if you get all males.

You are absolutely right! I do not want to breed the guppies! This might change in the future but since I am just starting out I think I will err on the side of caution and go for all males. Would five or six be okay?

This might seem like a silly question, but when doing water changes, how do I stop the temperature of the tank going down? Right now it doesn't really matter since I have no fish, but the temperature of the water drops 2/3 degrees when I do my water change and takes a couple of hours to return to normal. Is there something I should be doing to prevent this?

 

[NickAu]

This might seem like a silly question, but when doing water changes, how do I stop the temperature of the tank going down?

You don't, Just add the new water slowly. They will be fine.

 

[the_lock_man]

You are absolutely right! I do not want to breed the guppies! This might change in the future but since I am just starting out I think I will err on the side of caution and go for all males. Would five or six be okay?

This might seem like a silly question, but when doing water changes, how do I stop the temperature of the tank going down? Right now it doesn't really matter since I have no fish, but the temperature of the water drops 2/3 degrees when I do my water change and takes a couple of hours to return to normal. Is there something I should be doing to prevent this?

5 or 6 male guppies is perfect, you don't really want less than that, else one of them tends to get picked on.

I presume you are using only cold water during water changes? A temperature drop of 2 or 3 degrees is not really an issue, especially if your degrees are in Fahrenheit, rather than Celsius! In the wild, a rain storm can often lower the water temperature of the river/lake by a degree or two Celsius, so most fish are capable of withstanding that. If you're worried about it, then put some hot water in, or leave the water standing for a few hours, to allow it to reach room temperature.

Your fingers are good enough to be able to tell a rough temperature match.

 

[AbbeysDad]

You are not limited to guppies as all livebearers do well in hard water.
Your nitrates are at 20ppm which I consider to be an upper limit unless you have a well planted tank. So a water change is in order before adding fish. Also, adding fish just a few at a time is a wise move.
Finally, there's no good measure of how many fish to have in a given size tank as with good maintenance and water changes you can have many more fish than is otherwise the case. You just need to stay away from fish that will outgrow your tank, unless you can really have space and can afford to get more, larger tanks! If my math is right 85l is 22g. For avg livebearers, I'd say about 10 or so would do. Keep a watch on your nitrates and do water changes as necessary to keep low. Many suggest 50% weekly and be sure to use a good conditioner like Seachem Prime when doing water changes.
Good luck!

 

[ElizabethW]

I presume you are using only cold water during water changes? A temperature drop of 2 or 3 degrees is not really an issue, especially if your degrees are in Fahrenheit, rather than Celsius! In the wild, a rain storm can often lower the water temperature of the river/lake by a degree or two Celsius, so most fish are capable of withstanding that. If you're worried about it, then put some hot water in, or leave the water standing for a few hours, to allow it to reach room temperature.

It's Celsius; I'm a UK lass and we don't really use Fahrenheit here. But yes, I use cold water, although using warm wouldn't be a problem, I was just unsure of whether it would be okay.

You are not limited to guppies as all livebearers do well in hard water.
Your nitrates are at 20ppm which I consider to be an upper limit unless you have a well planted tank. So a water change is in order before adding fish. Also, adding fish just a few at a time is a wise move.
Finally, there's no good measure of how many fish to have in a given size tank as with good maintenance and water changes you can have many more fish than is otherwise the case. You just need to stay away from fish that will outgrow your tank, unless you can really have space and can afford to get more, larger tanks! If my math is right 85l is 22g. For avg livebearers, I'd say about 10 or so would do. Keep a watch on your nitrates and do water changes as necessary to keep low. Many suggest 50% weekly and be sure to use a good conditioner like Seachem Prime when doing water changes.
Good luck!

I think guppies would suit me fine, LFS doesn't have that big of a range but I would prefer to go to them rather than the big chain store that is further away. LFS has been really helpful and, as they're only a couple of streets away, they're in the same water area as me, so it'll be less stressful for the fish when the pH and hardness at LFS are practically identical to the tap water in my flat.

I haven't put any plants in yet. I'll be doing that next week, and I won't be putting any fish in until the nitrates have come down to a much lower level than they are currently. Are there any recommended plants to get for a first aquarium?

 

[Byron]

Given your water is on the hard side, Vallisneria is well suited. The smaller species, commonly referred to as corkscrew Vallisneria, is a lovely plant. Once settled, it will send out runners with daughter plants. These can be left where they arise, cut off and re-planted, or cut off and discarded. This is a superb plant for the smaller aquarium with hardish water.

Floating plants are also always a good idea, all fish like a roof above them. Water lettuce would do well here. It too will rapidly spread, but is easily kept within your preferred bounds by removing the larger plants at the water change.

Don't need to add my agreement really, but I totally agree with the other members on staying with males for livebearers. Guppies, Endlers, and platy could work in a 20g. Mollies and swordtails both get too large.

Byron.

 

[ElizabethW]

Given your water is on the hard side, Vallisneria is well suited. The smaller species, commonly referred to as corkscrew Vallisneria, is a lovely plant. Once settled, it will send out runners with daughter plants. These can be left where they arise, cut off and re-planted, or cut off and discarded. This is a superb plant for the smaller aquarium with hardish water.

Floating plants are also always a good idea, all fish like a roof above them. Water lettuce would do well here. It too will rapidly spread, but is easily kept within your preferred bounds by removing the larger plants at the water change.

Don't need to add my agreement really, but I totally agree with the other members on staying with males for livebearers. Guppies, Endlers, and platy could work in a 20g. Mollies and swordtails both get too large.

Byron.

Thanks for the suggestions, I'll see if LFS has them. It doesn't matter if they need cutting back or anything like that, I'm a gardener by trade so I will be fine with it and if there's any to be taken out I'll add them to my green compost. I seem to remember that I have an aquatic gardening book around the house somewhere, back from when I had an algae tub, so I'll dig that out and see if it has any more ideas for suitable plants.

 

[AbbeysDad]

Amazon Swords, Anubias Nana, Java Fern, Java Moss, Dwarf Sag, Water Wisteria, Crypts, Staurogyne repens...

 

[Byron]

It might be useful to review your lighting. There would be no point in getting an assortment of plants only to have them turn to mush because of insufficient light (or too much).

 

[AbbeysDad]

It might be useful to review your lighting. There would be no point in getting an assortment of plants only to have them turn to mush because of insufficient light (or too much).

Absolutely as a lot of the ensembles sold (tank, hood, stand...) have lighting that's fine for viewing fish, but not for supporting plant growth!