Covering Filter Outlet To Make It Shrimp Safe

My shrimps are in a bigger tank than yours (50-ish litres) and I use an Eheim aquaball in there. Unfortunately, even the smallest of these filters is a bit strong for my 25 litre QT. When there are fish in that tank I have to do unsightly things to the filter to slow down the flow - attaching a piece of sponge over the outflow with an elastic band. It isn't very pretty but then it is only a QT.

However, in my betta's tank (~26 litres) I have an internal filter which I think would work well with shrimps. It's one of Maidenhead Aquatics filters, the aqua internal 50. It has several output options including a mini spray bar with a flow rate adjuster. I had it set very slow, just a trickle really, when my last betta was lying on the bottom and having trouble swimming. The media is a hollow sponge with carbon inside, perfect for removing the carbon and stuffing ready cycled sponge inside - that's what I did when I replaced a very old Hagen mini filter. I just had to cut a slice off the bottom to make room for all the old sponge.
When I realised the Hagen filter didn't have much life left, this was the only filter I found for a tank that size that I was happy with. So many filters for tanks this size have carbon cartridges as the only media, and even worse was the replacement for the Hagen mini which has nothing but zeolite and carbon inside. I was just so happy to find a small filter that actually had sponge inside.

Hi Sue,


The new filter that you reccomended has arrived and is now set up in  my shrimp tank. I did as you said – took out the carbon from the centre and added my cycled filter media that was in the tank originally.

The spray bar is sitting just above the water line as pictured in the instructions and I have it turned down low – just enough to ripple the surface really.

What a great design! Thanks so much for providing the link. I'm toying with getting a bigger version as a spare for my community tank now!

Yes, it is a bit flimsy, but overall I'm very pleased  :)with it.

I like this filter too for my betta's tank. No danger of him being sucked against it or blown across the tank.

Hi AdyDnt,

The instructions say to have the topmost few centimetres and the spray bar clear of the water. It works really well in my shrimp tank and I'm very pleased with it

I've run it both ways, with the spraybar above the water and with the holes just under the surface. It works fine both ways.

Quick question about the Aqua Internal 50 (Maidenhead Aquatics) internal filter.
It's currently in my 23 litre shrimpery and coping very well with that amount of water.
However, I'm going to be adding 10 micro rasbora in the next couple of weeks and I don't really think this tank is big enough (where have you heard this tale before, I wonder?).
I've been offered a free 64 litre bare tank, which I think would be much better. My problem is that I really like this filter and I don't want to change it.
I know that by the time the decoration and substrate are in this tank, there won't be 64 litres of water in it, but my question is, will the Aqua Internal 50 be big enough to cope with the amount of water (60 litres?) in the new tank or not?

As ever, thanks in advance peeps!

Thanks Sue,

For the moment, no more than 10 microrasboras, 10 ember tetras and the shrimp.
If I were to put anything else in, I have another small filter that I could add at the opposite end of the tank.