06.04.2026 | LED Lighting

LED Aquarium Lighting: Spectrum, IP Ratings and Power Selection Guide

LED aquarium lighting is mounted above the water: an IP20 strip in a closed aluminium profile with a diffuser above a covered aquarium, and above an open-top aquarium a strip rated at least IP65 (splash protection); 2K-Trade does not sell submersible strips. For planted tanks the key spectral ranges are 440-460 nm (blue) and 640-660 nm (red), which are used in photosynthesis. The general colour-temperature recommendation for a freshwater planted tank is 6000-6500 K; ranges vary by tank type — for fish-only tanks 4000-6000 K is enough. Typical brightness: from 10-20 lm per litre of water (fish only) to 60-120 lm/L (plants needing strong light). 2K-Trade offers the 140 LED/m 24 V IP65 LED strip (9.6 W/m) for mounting above an open aquarium and aluminium profiles with diffusers that protect the strip from moisture.

LED aquarium lighting is a niche but rapidly growing application of LED technology. LEDs are replacing traditional fluorescent tubes and HQI lamps thanks to lower energy consumption, longer life (30,000-50,000 hours vs 6,000-10,000 for fluorescent tubes) and the possibility of precise spectrum selection. This article covers the technical requirements, parameter selection and installation of LED lighting for freshwater and marine aquariums.

Lighting requirements of an aquarium

Aquarium lighting has three functions: biological (plant photosynthesis, the daily rhythm of fish), aesthetic (showing the colours of fish and decorations) and technical (algae control). The lighting parameters are chosen first of all according to the tank type.

Planted freshwater tank

Aquatic plants need light of a suitable spectrum and intensity for photosynthesis. Key spectral ranges:

440-460 nm (blue) — one of the two ranges used most strongly in photosynthesis.
640-660 nm (red) — the second range used most strongly in photosynthesis; supports stem and leaf growth.
520-560 nm (green) — largely reflected by plants (which is why they look green), less important for photosynthesis, but it improves the natural look of the tank.

Colour temperature: 6000-6500 K (cool white) is the general recommendation for a freshwater planted tank — this colour imitates daylight and has a high blue content. The ranges vary by tank type (see below: fish-only and marine tanks).

Fish-only tank

Tanks without live plants have lower lighting requirements. Light mainly serves to show the colours of the fish and keep their daily rhythm. A colour temperature of 4000-6000 K (neutral to cool white) renders the natural colours of fish faithfully. Light that is too warm (3000 K) mutes the blue and green colours of tropical fish.

Marine tank (reef/marine)

Marine tanks with corals need the highest lighting power and a specific spectrum. Symbiotic corals need light of 10,000-20,000 K (strongly blue) to sustain their zooxanthellae. Additional spectrum: 420-460 nm (actinic blue) stimulates coral fluorescence. In this application LED strips supplement dedicated spot fixtures.

How many lumens per litre of water

Aquarium lighting intensity is measured in lumens per litre (lm/L). It is a simplified but practical measure used in fishkeeping.

Tank type	Lumens/litre	Example: 200 L tank	Description
Fish without plants	10-20 lm/L	2000-4000 lm	Minimum lighting, showing the fish
Undemanding plants	20-40 lm/L	4000-8000 lm	Anubias, Cryptocoryne, mosses — shade-loving plants
Moderately demanding plants	40-60 lm/L	8000-12,000 lm	Vallisneria, most stem plants
Demanding plants	60-120 lm/L	12,000-24,000 lm	Carpet plants, red plants, Dutch-style tanks
Marine with corals	80-150 lm/L	16,000-30,000 lm	Hard corals SPS, LPS, soft corals

The values are indicative. Deeper tanks need a greater luminous flux, because water absorbs part of the light — the deeper the tank, the more lumens are needed for the light to reach the bottom.

IP rating — the key parameter

In aquarium applications the IP rating (Ingress Protection) is critical. The mounting location of the LED strip determines the required rating:

Mounting	IP rating	Description
Above the aquarium (hood, frame)	IP20 (in a profile with a diffuser)	No direct contact with water, but exposure to water vapour
Above the aquarium (no hood)	at least IP65	Exposure to splashes and water vapour; in the 2K-Trade range: 140 LED/m 24 V IP65 strip
On the aquarium edge or under water	IP67 / IP68	Contact with water or immersion — strips of these ratings are not in the 2K-Trade range; this article is about mounting above the water

Even when mounted above the aquarium (IP20 in a profile), moisture is a constant threat. Water vapour condenses on cooler surfaces (the aluminium profile) and can enter the LED channel through leaky end caps. Recommendation: use end caps with silicone sealing and ventilate the aquarium hood.

LED strips for an aquarium — selection

Choosing an LED strip for an aquarium depends on three factors: the required lighting intensity (lm/L), the spectrum and the mounting location.

Monochromatic (white) strips

The most commonly used in fishkeeping. A 6000 K strip gives a good spectrum for plants (high blue content) and renders fish colours faithfully. Recommended models from the 2K-Trade range:

LED strip 140 LED/m 24V IP20 (9.6-14.4 W/m) — for mounting in a profile above the aquarium
LED strip Hi-Eff 192 LED/m 24V IP20 (14-20 W/m) — for planted tanks that need high brightness
LED strip 140 LED/m 24V IP65 (9.6 W/m) — for mounting above an open-top aquarium (splash protection)

CCT strips (adjustable colour temperature)

CCT 120 LED/m 24V IP20 strips allow the colour temperature to be adjusted from 2700 K to 6000 K. They make it possible to simulate the natural daily cycle: cool light (6000 K) at midday, warmer (4000 K) in the morning and evening. Particularly beneficial for tropical fish, which in nature experience spectral changes during the day.

RGB and RGBW strips

RGB 60 LED/m and RGBW strips allow the spectrum to be matched precisely to the needs of specific plants. By mixing the R, G and B channels, light of any shade can be obtained. In marine fishkeeping: maximising the blue channel (420-460 nm) to stimulate coral fluorescence.

Installing LED lighting above an aquarium

The most common way to install LED aquarium lighting is in an aluminium profile fixed to the aquarium hood or on a stand above it. Installation steps:

Measuring — measure the length of the aquarium. The profile should be 2-4 cm shorter than the tank length (margin for end caps).
Cutting the profile — cut the aluminium profile to the measured length with a hacksaw.
Fitting the strip — stick the LED strip into the channel of the profile. For planted tanks — 2 or 3 rows of strips in a wide profile (e.g. GAMMA 50, channel approx. 45.6 mm) for higher brightness.
Diffuser and end caps — close the profile with a frosted diffuser (spreads the light evenly over the bottom of the tank) and sealed end caps.
Fixing — mount the profile on the aquarium hood or on the frame. Distance from the water surface: min. 5-10 cm (for IP20) or directly above the water (for IP65).
Power supply — connect a 24V DC power supply. Place it outside the splash zone (on the cabinet, behind the aquarium). A controller with a timer allows automatic control of the photoperiod (8-12 hours of light per day).

Photoperiod — how many hours of light per day

The lighting time of the aquarium (photoperiod) affects plant growth and algae control:

6-8 hours — tanks with low light demand, fighting algae, new tanks in the stabilisation phase
8-10 hours — the standard for most planted tanks
10-12 hours — heavily planted tanks with CO2 dosing and fertilisation

Too long a photoperiod (over 12 hours) encourages an algae bloom, especially in tanks without CO2 dosing. A controller with a timer is a mandatory element of the installation — it removes the risk of forgetting to switch the lighting off. Controllers with a timer function are available in the category drivers for LED strips.

LED vs fluorescent tubes — comparison

Parameter	LED	Fluorescent tube
Lifetime	30,000-50,000 h	6,000-10,000 h
Energy consumption	Lower	Baseline
Replacement	Every 8-14 years	Every 1-2 years
Water heating	Minimal	Significant (IR)
Spectrum selection	Precise (RGB, CCT)	Limited to the manufacturer’s models
Dimming	Yes (PWM dimmer)	Requires a special ballast
Form	Flexible (strip, profile)	Rigid tube
Initial cost	Higher	Lower
Running cost (5 years)	Lower (no replacement)	Higher (2-3 replacements)

Frequently asked questions

Is an IP20 LED strip suitable for an aquarium?

Yes, provided it is mounted in a closed aluminium profile with a diffuser and sealed end caps, placed at least 5-10 cm above the water surface. The profile protects the strip from water vapour and splashes. In open-top tanks (no hood) it is safer to use an IP65 strip.

Which colour temperature should I choose for a planted tank?

6000-6500 K (cool white). This temperature provides the high blue content needed for photosynthesis and at the same time renders the colours of plants and fish faithfully. For marine tanks: 10,000-20,000 K (strong blue).

How much LED strip do I need for a 100-litre aquarium?

It depends on the tank type. Fish-only tank (20 lm/L): 2000 lm needed. Planted tank (60 lm/L): 6000 lm. Divide the required flux by the luminous flux per metre of the strip given in its technical data — that gives the strip length you need. For a standard tank 60-80 cm long, 2-3 rows of LED strips in a wide profile are optimal.

Does LED lighting cause algae growth?

Not the LED lighting itself, but a wrong photoperiod and a lack of biological balance. Algae develop when: (1) the photoperiod exceeds 10-12 hours, (2) there are no live plants competing for nutrients, (3) no CO2 is dosed under strong lighting. A controller with a timer and gradually increasing the photoperiod in a new tank (from 6 h) minimise the risk.

Can I submerge an LED strip in water?

Only IP68 strips are intended for permanent immersion. IP67 strips withstand brief immersion. IP65 and IP20 strips are not suitable for immersion — IP65 protects against splashes, IP20 only against dust. IP67 and IP68 strips are not in the 2K-Trade range; the IP65 strip is available for mounting above the aquarium without contact with water.

Summary

LED aquarium lighting is an energy-saving and long-lived alternative to fluorescent tubes. The key selection parameters: colour temperature (6000-6500 K for plants, 4000-6000 K for fish), lighting intensity (10-120 lm/L depending on the tank type) and IP rating (IP20 in a profile above the water, at least IP65 above an open-top aquarium; submersible strips are not in the 2K-Trade range). A photoperiod of 8-10 hours a day with a timer controller prevents algae growth.

LED strips, power supplies and controllers with a timer function can be found in the categories LED strips and drivers for LED strips in the 2K-Trade catalogue. For questions about choosing lighting for a specific aquarium — contact the technical team.