I have 13 small goldfish in my tank which is 4foot long,2 and half foot tall and 2 foot wide, do you think I have too many in the tank, I have an external fluval 204 filter, if its not too many how many more can I add???
oh and as for more you "could" fit another 2 goldfish if you go by the 8 gall per fish rule but as i guess you have gravel/sand and ornaments id say you have reached your limit
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TheDragonLord wrote: your tank is 120 uk gallons so i'd say no but you will probably need another external filter
Are you sure on that Chris as I have a 4ft tank 48x12x12 and it is only 30 gallons although your tank is taller and wider mermaid, remember you should allow for air space rather than hight
All I have in my tank as decoration goes (I am not to keen on that to be honest) I have a castle in the corner and medium sized pebbles scattered across the bottom of the tank. My filter is very powerful attached to it inside the tank is a spray tube designed for that filter so that they have plenty of oxygen, and the water current is quite fast.
what about your water quality, you need to do a test to see where your tank is at, it doenst really matter what size it is or how many fish u have, at the end of the day, its the environment they live in which will tell you whether what you have is substantial for the number of fish in there. If your water quality is spot on then you need to consider if your fish are fully grown and how much a demand adding any extra fish will put on your system.
Dimensions: 122cm L x 61cm W x 61cm H/48" L x 24" W x 24" H Volume: 452 l./100 gal. Volume after displacement: 407 l./90 gal. Surface area: 0.74 sq m/8.00 sq ft
13 goldfish times 8 = 104
So i would say no more fish, you will be overstocked when the fish you have now become fully grown. di
although your tank is taller and wider mermaid, remember you should allow for air space rather than hight 
