The Resun auto feeder is an automatic fish feeder designed for aquariums and pond tanks that dispenses dry food (flakes, pellets, granules) on a programmable schedule. If you've seen it and you're wondering whether it's worth buying, the short answer is: it's a functional, no-frills feeder that does what it promises at a price point well below most competitors, with some reliability caveats you should know before buying.
This guide covers the Resun auto feeder's specifications, how to set it up, what it handles well, where it falls short, and how it compares to other options in the same category.
What the Resun Auto Feeder Is
Resun is a Chinese aquarium equipment manufacturer that makes a broad range of products including pumps, heaters, filters, and automatic feeders. Their auto feeder line includes several models, with the most common being the AF-2005D and the AF-2009D.
AF-2005D: Basic model, battery-powered (2 AA batteries), up to 4 feedings per day programmable, drum capacity approximately 100ml, fits tank rim widths up to about 1 inch.
AF-2009D: Slightly more advanced model, similar drum capacity, same battery requirement, some models include a USB charging option, and in some versions a moisture-barrier fan to keep food dry.
Both models are drum-style feeders. Food loads into a rotating drum with an adjustable opening. Each feeding, the drum rotates a set number of turns and dispenses a portion of food through the opening into the tank. Portion size is controlled by the duration of each dispense (adjustable on the unit) rather than by weight.
Retail pricing runs $15 to $30 on Amazon depending on the specific model and current promotions. At that price point, the Resun competes with the Zacro Auto Fish Feeder and the Eheim Everyday Fish Feeder as a budget option, while sitting well below the Eheim 3581 Digital Feeder ($45 to $60) and the Hydor Automatic Fish Feeder ($50 to $65).
Setting Up a Resun Auto Feeder
Setup takes 10 to 15 minutes. The unit clips onto the top rim of the aquarium via an adjustable clamp. The drum opens at the bottom, and you load food from the top by removing the drum cap.
Step-by-Step Setup
- Install batteries (two AA, not included). The display activates and prompts you to set the current time.
- Set the time using the Mode, + and - buttons. The display is small and the button labels are occasionally in Chinese on imported units, but the sequence is logical once you understand that Mode cycles through hour, minute, and confirmation.
- Set feeding times. You can program between 1 and 4 daily feedings. Each feeding is assigned a time in 24-hour format.
- Set dispense duration. This is labeled "F-Time" or "Feed Time" on most units. Options are typically 1 to 6 seconds per turn. Start at 2 seconds and observe how much food drops. Adjust from there.
- Load food. Remove the drum cover, fill to the max line (about 100ml), replace the cover.
- Clamp the unit to the tank rim so the dispense opening is centered over the water.
Test the unit manually (there's a button to trigger an immediate dispense) before setting it to automatic. Watch where food lands and confirm it's dispersing into the water rather than landing on the rim or being blocked by equipment.
What the Resun Feeder Does Well
Basic scheduling: For a simple 1 to 4 times per day schedule, the Resun works. Once set up correctly, it will dispense food at the programmed times reliably for months on standard batteries (typically 3 to 6 months on 2 AA batteries with four feedings per day).
Flakes and small pellets: The drum design handles dry flake food and small pellets (2mm and under) well. Food flows through the opening without bridging as long as you don't overfill the drum.
Vacation coverage: The primary use case for most buyers is vacation feeding. A 7 to 10 day trip is well within the Resun's reliable operating window on fresh batteries.
Price: At $15 to $25, the Resun is the lowest-cost viable option for automatic feeding. If your requirements are simple, it's hard to justify spending three times as much for the Eheim 3581.
Where the Resun Feeder Falls Short
Moisture sensitivity: Without a fan system to circulate air in the drum, food in humid environments (particularly above a saltwater tank or in a humid room) can absorb moisture and clump. Clumped food jams the drum opening and causes missed feedings or large clumps dumping at once when the jam clears. If you're running a saltwater tank, this is a real concern. Look for the AF-2009D version with a fan, or take the simple precaution of not overfilling the drum.
Portion consistency: The drum-rotation timing system is not as precise as a wheel-based system (like the Eheim everyday feeder). Portion size varies slightly between feedings, which is fine for casual feeding but not ideal if you're trying to dial in exact rations.
Programming interface: The display is small, the instructions are often translated poorly, and the programming mode cycles through options without backlighting, making it hard to confirm settings. Once it's set correctly it stays set, but the initial setup can be frustrating.
Large pellets and stick food: Pellets over 3mm tend to jam at the drum opening, and stick-style foods (like freeze-dried krill) don't dispense reliably from the drum design.
Build quality: Plastic construction, clips that can flex and shift over time. If the unit clips to a thin tank rim without a secure lock, vibration from a nearby powerhead can cause it to shift position or fall. Add a zip tie through the clamp bracket if you're worried about stability.
Resun vs. Competitors
vs. Eheim Everyday Fish Feeder (3581)
The Eheim 3581 is the standard recommendation in the hobby for good reason. It uses a wheel-rotation mechanism that provides more consistent portion sizes, has better moisture resistance, holds more food (100ml drum), and has a more intuitive interface. At $45 to $55, it's roughly twice the price of the Resun. If you keep fish long-term and use an auto feeder regularly, the Eheim is worth the extra cost. For occasional vacation use, the Resun is adequate.
vs. Zacro Automatic Fish Feeder
The Zacro is in the same price range as the Resun and has a similar drum design. User experience between the two is comparable; some hobbyists prefer the Zacro's interface slightly, but build quality and performance are essentially equivalent. Buy whichever is cheaper when you're shopping.
vs. Hydor Automatic Fish Feeder
The Hydor is a mid-tier option ($50 to $65) with a rotating drum, adjustable portion size, and a more robust build. It's a step up from the Resun without reaching the price of premium units like the JUWEL AutoFeeder.
If you're comparing auto feeder options for a marine tank setup, the Best Auto Top Off Tank guide is also worth reviewing since keeping water level consistent is directly tied to salinity stability when you're away for a vacation. The Best Auto Top Up Container guide covers reservoir options for the freshwater side of your ATO system.
Tips for Getting Better Performance from the Resun
Use small, dry food. Pellets under 2mm and dry flake food work best. Avoid freeze-dried foods, large pellets, or anything with any moisture content.
Don't overfill. Fill the drum to 70 to 80 percent of capacity. A fully loaded drum increases pressure on the food and increases clumping risk.
Use fresh batteries. Battery life affects motor torque. Weak batteries can cause the drum to stall mid-rotation, resulting in partial feedings or no feeding. Change batteries every 3 to 4 months rather than waiting for failure.
Position correctly. Adjust the clamp so food drops into open water, not onto rock, equipment, or the tank rim edge. Food that misses the water surface is wasted and produces ammonia as it decays.
Test before leaving for vacation. Run the feeder for two to three days before a vacation and observe the feeding results. Verify the portions are appropriate and food is actually reaching the fish before relying on it unsupervised.
FAQ
How long do batteries last in the Resun auto feeder? Under normal use (two to four feedings per day), two AA batteries last approximately three to six months. Fresh alkaline batteries perform better than older or economy batteries. Replace before a long trip.
Can I use the Resun feeder on a saltwater tank? Yes, but moisture from evaporation over a saltwater tank makes food clumping more likely than on a freshwater tank. Use the AF-2009D model with the fan option, or add a silica gel packet inside the drum chamber to absorb humidity.
What's the maximum feeding amount per session? This depends on the dispense time setting and drum opening width. At maximum settings, the Resun dispenses roughly one teaspoon per feeding, which is a lot for most tanks. Start at the minimum setting and increase gradually. Most tanks do fine at 2 to 3 seconds of dispense time.
Will the Resun work with a turtle or large fish tank? The small drum (100ml) limits its use to smaller fish that eat flake or small pellet food. For turtles or large fish that require large pellets or stick foods, a larger capacity feeder designed for those food types (like the Fish Mate F14 for pond fish) is more appropriate.
Summary
The Resun auto feeder is a reasonable budget option for basic vacation feeding of small fish that eat flakes or small pellets. It's not the most reliable feeder on the market, and the programming interface is awkward, but at $15 to $25 it delivers acceptable performance for the price. For daily long-term feeding with consistent portions, spend the extra $25 to $30 and get an Eheim 3581. For a one-time vacation setup on a freshwater tank, the Resun gets the job done.