How many fish can I keep in my 138 liter tank?

FishForums.net Pet of the Month
🐶 POTM Poll is Open! 🦎 Click here to Vote! 🐰

Blackwater guru

Fish Fanatic
Joined
Dec 22, 2019
Messages
129
Reaction score
126
Location
Sweden
In early january this year I got my first freshwater aquarium set up and it currently hosts 10 cardinal tetras and 4 corydoras duplicareus catfish although I am going to add a group of small hatchet fish and 10 xray tetras along with 5 more cardinals.

image (1).jpg


Would that be too many fish or not?

I am eventually going to add birch branches into the tank along with dried oak leaves to transform it into a blackwater setup.
 
In early january this year I got my first freshwater aquarium set up and it currently hosts 10 cardinal tetras and 4 corydoras duplicareus catfish although I am going to add a group of small hatchet fish and 10 xray tetras along with 5 more cardinals.

View attachment 96927

Would that be too many fish or not?

I am eventually going to add birch branches into the tank along with dried oak leaves to transform it into a blackwater setup.
This should be a sufficient amount of space for the tetras, although i’m not too sure about hatchet fish but I do know they don’t move much. As for the cories I would encourage you to get a large group of probably 6-8 instead of just the 4.
 
Hatchet fish are a shoaling fish and are quite shy and nervous fish, the larger group they are kept in the safer they will feel, they are easily startled and will jump so make sure you have a lid that covers the whole tank and that the water level is a little below the lip as they can also jump and bang off the glass top. They are exclusive top feeders and will spend the wide majority of their time parked at the very top of the tank in a shoal.
Good luck personally i prefer marbled hatchets over just the silver ones and the marbles stay a little smaller.
 
Answering your direct question is impossible because of the several factors involved. Many sites will assume numbers of fish of a specific length will go in a tank of a certain volume, but that is not even close to actually answering the question. One has to consider the tank dimensions more than the volume in most cases, as well as the inherent behaviours and requirements of the species (how many of a species is necessary, what water flow, water parameters, light, aquascaping...etc).

You definitely need to increase the Corydoras duplicareus, no doubt about that; assuming the tank dimensions are no less than 30 inches (75 cm) by 12 inches (30 cm), a group of 9-12 of this cory would be needed. I first acquired this species a year or two after it was discovered (1994) and described (1995) by David Sands, and I have had it ever since. It is a very social species.

As for additional species, I need to know the dimensions of the tank.
 
Answering your direct question is impossible because of the several factors involved. Many sites will assume numbers of fish of a specific length will go in a tank of a certain volume, but that is not even close to actually answering the question. One has to consider the tank dimensions more than the volume in most cases, as well as the inherent behaviours and requirements of the species (how many of a species is necessary, what water flow, water parameters, light, aquascaping...etc).

You definitely need to increase the Corydoras duplicareus, no doubt about that; assuming the tank dimensions are no less than 30 inches (75 cm) by 12 inches (30 cm), a group of 9-12 of this cory would be needed. I first acquired this species a year or two after it was discovered (1994) and described (1995) by David Sands, and I have had it ever since. It is a very social species.

As for additional species, I need to know the dimensions of the tank.

I do know that the tank is 1 meter long but I am unsure of the height and it probably is somewhere around 30 to 100 centimeters long because it looks more like a rectangle in terms of shape.

I am currently close to finishing the fish in cycle because I started it in early january and it is supposed to take 4 to 6 weeks in total according to the guy working at the lfs and that I can add more fish to it once that has finished.

The reason as to why I only have 4 is that a website recommended to keep 4 to 6 of these and they were the fish I used to start the fish in cycle.

What I do know is that the water flow is slow as to not stress them out too much and in terms of filtration it uses an undergravel filter with a powerhead.

Someone else mentioned you need a strong cover for the hatchetfish and indeed I do have a strong cover and I will add them once there are enough floating plants to make them feel safe.

I am still a newbie but I am learning from these tiny mistakes although I did tons of research for several months before getting everything setup to avoid major mistakes often by newbies such as overfeeding and keeping them in a too small of a tank.
 
Can you measure the tank and post exact measurements for length height and depth?
What are your water parameters and conditions?
GH is often missed but very important when choosing fish, you might find it on your water providers website, or post a link If you can't see it.
 
Can you measure the tank and post exact measurements for length height and depth?
What are your water parameters and conditions?
GH is often missed but very important when choosing fish, you might find it on your water providers website, or post a link If you can't see it.

I don't have a test kit yet although I really want one badly.

What I do know is that the tap water at home that I use is soft and that the ph is a bit lower which means it must be somewhere a bit under 7 and that it comes from an underground well and this in the swedish countryside.

I also forgot to mention I am not the only one who manages the tank because both me and my dad have been working on it and currently I am 18 years of age.

I will measure it eventually but I can not do that at the moment because I only come home every two weeks because I have to go at a boarding school in another region.
 
Gotcha.
Maybe your dad could get you some of the data, it really will help get the right fish for your setup. It will be great if you could get a test kit, meanwhile your water suppliers website might show an average pH, GH and KH so you know what your working with. Ask your dad which company supplies the water.

I like your stocking plans which utilises the top, middle and bottom swimming spaces. Looking forward to seeing it develop. :)
 
Gotcha.
Maybe your dad could get you some of the data, it really will help get the right fish for your setup. It will be great if you could get a test kit, meanwhile your water suppliers website might show an average pH, GH and KH so you know what your working with. Ask your dad which company supplies the water.

I like your stocking plans which utilises the top, middle and bottom swimming spaces. Looking forward to seeing it develop. :)
Gotcha.
Maybe your dad could get you some of the data, it really will help get the right fish for your setup. It will be great if you could get a test kit, meanwhile your water suppliers website might show an average pH, GH and KH so you know what your working with. Ask your dad which company supplies the water.

I like your stocking plans which utilises the top, middle and bottom swimming spaces. Looking forward to seeing it develop. :)

well we do not have a company that supplies the water in fact my dad is the one who manages the tap water at home so all I have to do is ask.
 
The tank size is resolved; a 138 liter (36 gallon) with a length of 90 cm (3 feet, one meter). Now we just need to know the water parameters, being GH (general or total hardness) and pH.
 

Most reactions

trending

Staff online

Members online

Back
Top