thin film or the water's surface, fish gasping - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 4 Old 07-26-2010, 05:56 PM Thread Starter
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thin film or the water's surface, fish gasping

hello all im new to the forum(been lurking hahaha), anyway recently ive had a weird problem with my tank. There seems to b this thin film on the surface of the water, it looks almost like oil. i try to remove it but it just returns later in the day. When i disturb the water tension the film dissipates but it simply returns. I run a Fluval 405 with just sponges and biomax, i do about 2, 5-10% water changes once a week and i use Seachem Prime water conditioner. i use nutrafin liquid fertilizer once a week. i researched this film but i havent found any conclusive results on what it is. also the fish seem to gasping more than they have in the past. Im wonder if the plants i have arent oxygenating the water sufficiently? maybe some weird ammonium issues? maybe the plants arent receiving enough nutrients to oxygenate the water?

Its a 46gallon corner tank


Fish:(sorry i dont kno all the scientific names)
4 Bolivian rams
10 Black Phantom tetras
6 Diamond tetras
6 Neon Tetras
1 Rummy nose(hemmigramus blehri) i kno he needs friends
6 albino corys

the tank is heavily planted:
7-10 large Sword plants
java moss
java ferns
various crypts
4-5 large anubias

any help or information is greatly appreciated.
bboyle9 is offline  
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post #2 of 4 Old 07-26-2010, 06:05 PM
try doing a large water change and cleaning the filter

5x2x2 aro,highfin bat,fei feng,ST,albino tinfoil,c.perch
4x1.5x1.5 planted tetras,harlequins,
otto,WMM,2 types of celebes rainbows,rcs,amano, bamboo,red ramhorns,MTS
3.5x2.5x2 flowerhorn,pleco
3x1.5x1.5 russel's lion,blue cleaner,sixline and leopard wrasse,maroon clown pair,green chromis,scorpion,tiger cowrie,turbo,lyretail anthias,jewel,anemone,star polyp,marbled and giant green mushi,zoa
2x1x1 nano sw shrimps
22 May 2012
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post #3 of 4 Old 07-26-2010, 07:28 PM
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Welcome to Tropical Fish Keeping forum.

I would be fairly certain you have two quite distinct issues.

First the scum on the surface sounds like a common protein scum. This can form on the surface of any aquarium, though it seems more prevalent on some than others. It is not directly harmful but should be regularly siphoned off (I simply invert the water changer and siphon off the surface during the weekly water change) since it will reduce the gaseous exchange. A filter that has a gentle flow across the surface will usually keep this at bay. I used to use surface skimmers on my canisters and they handled this, but I stopped (very small fish and fry got sucked in) and I see it but usually only on one tank.

I say gentle flow because surface disturbance speeds up the gaseous exchange and CO2 is driven off before the plants can use it, which in a planted tank can be detrimental to the plants.

The other issue may be related to the temperature. For the fish you mention, it is not necessary to have the tank as warm as 81 or higher. A temperature around 77-78F would be adequate. Some of those fish can tolerate warmer temps long-term (rummynose), but others like the neon cannot. Neons should never be above 77-78F, and they would be very happy at 75F. The Bolivian Ram the same, the corys also. Diamond Tetra and Black Phantom Tetra have ranges from 75-82 but there is no harm in maintaining them at the lower end. All of these (except for the neons) can be kept above 80F but should not be unless there are fish in the aquarium requiring that temperature (Discus, Mikrogeophagus ramirezi, some gourami, etc). You can check temperature ranges for fish in our profiles, click on the shaded name in posts or use the second tab from the left in the blue bar across the top.

Higher temperature means less dissolved oxygen in the water, and fish will naturally have to respirate more to obtain oxygen. With the plants you mention, provided they are photosynthesizing (the nitrate at zero says to me that they are), there should be no shortage of oxygen, but again, it will be naturally less with warmer temperatures. The slow growers may not make much of a difference, but swords (Echinodorus species) are high oxygenators and relatively fast growing though not comparable to many of the stem plants. But still sufficient for your setup.

Lowering the temperature may help the protein scum too; I have noted it is more prevalent on my warmer tank (SE Asian housing Chocolate and pygmy gourami) whereas it rarely if ever appears on the Amazonian tanks. Some think it also (like cyanobacteria) bears a relation to plants in the Cryptocoryne genus; I've no evidence either way, except I have crypts in that tank and not the others.

Kitten's suggestion on the filter is very relevant too. If the filter is slowing due to clogged media/pads, this can cause the fish to respirate more rapidly. I had this in my 115g Amazonian tank not long ago. I noticed one evening as I watched the fish that some of the corys seems to be breathing faster than normal, and they were just sitting on a log. Other fish were fine. So I started looking around the tank, and noticed the flow from the filter was less than normal, as the plants immediately in front were not moving at all, and usually they do slightly. I shut off the filter, opened it up, and saw it was obviously overdue for a cleaning, so I rinsed it out. Within an hour, the corys were back to normal. The reduced water flow meant they had to work a bit harder to get the oxygen they wanted. So that is worth remembering.

Hope this helps.


Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]

Last edited by Byron; 07-26-2010 at 07:34 PM.
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post #4 of 4 Old 07-27-2010, 03:00 PM Thread Starter
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the temp. and water flow issues make complete sense. it has been awful hot here this summer and im wondering if the increased humidity in the air is retaining more heat and increasing the temp more than i recognize. ill reduce the temp and clean the filter and let u kno how it goes, thank you for the input its much appreciated.
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