{"id":2900,"date":"2025-11-25T20:16:15","date_gmt":"2025-11-25T19:16:15","guid":{"rendered":"https:\/\/www.ancistrus.at\/2025\/11\/25\/5-common-mistakes-when-keeping-ancistrus-in-a-community-tank\/"},"modified":"2026-01-08T19:32:47","modified_gmt":"2026-01-08T18:32:47","slug":"5-common-mistakes-when-keeping-ancistrus-in-a-community-tank","status":"publish","type":"post","link":"https:\/\/www.ancistrus.at\/en\/2025\/11\/25\/5-common-mistakes-when-keeping-ancistrus-in-a-community-tank\/","title":{"rendered":"5 common mistakes when keeping Ancistrus in a community tank"},"content":{"rendered":"

[et_pb_section fb_built=”1″ admin_label=”section” _builder_version=”4.27.4″ background_color=”RGBA(255,255,255,0)” custom_margin=”0px||||false|false” custom_padding=”0px||||false|false” global_colors_info=”{}” collapsed=”on”][et_pb_row admin_label=”row” _builder_version=”4.27.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”0px|||||” global_colors_info=”{}”]Bristlenose catfish of the genus Ancistrus<\/em> are among the most popular armored catfish in aquaristics. They remain relatively small, usually 10-13 cm, eat algae and biofilm, and are considered robust aquarium fish found in many community tanks. Nevertheless, Ancistrus are often underestimated in daily practice \u2013 leading to typical keeping mistakes that can result in long-term stress, diseases, or damage to the aquarium setup. <\/p>\n

This post is about five common mistakes when keeping Ancistrus<\/em> in a community tank \u2013 and how to avoid them, so that bristlenose catfish can truly live healthy and species-appropriate lives in the long term.[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”3_5,2_5″ admin_label=”row” module_class=”bildok” _builder_version=”4.27.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” global_colors_info=”{}”][et_pb_column type=”3_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”0px|||||” global_colors_info=”{}”]<\/p>\n

1. Tank too small and insufficient structure<\/h3>\n

Many aquarists place Ancistrus<\/em> as a “cleanup crew” into the next best aquarium without considering their eventual size and territorial behavior. Even if bristlenose catfish remain small compared to large “Plecos,” they still require sufficient floor space, hiding places, and retreat options. <\/p>\n

Adult Ancistrus<\/em> males can be quite territorial and claim preferred caves or root areas for themselves. In aquariums that are too small and lack sufficient hiding places, constant skirmishes can occur, recognizable by torn fins, stress coloration, and feeding marks on the odontodes. A tank of about 80-100 cm in length with several well-distributed caves, roots, and rock structures is significantly better suited for harmonious coexistence. <\/p>\n

Structure in the tank is important not only for territorial behavior but also for the natural behavior of Ancistrus<\/em>: They graze on biofilm from roots and stones, rest under overhangs, and seek out shady areas. A crystal-clear, “sterile” aquarium without decoration is unsuitable for bristlenose catfish. <\/p>\n

[\/et_pb_text][\/et_pb_column][et_pb_column type=”2_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_image src=”https:\/\/www.ancistrus.at\/wp-content\/uploads\/2025\/11\/Aquarium-fuer-Antennenwelse-Ingo-Seidel-600×400.jpg” alt=”Aquarium for Bristlenose Catfish” title_text=”Aquarium for Bristlenose Catfish” _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”][\/et_pb_image][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n

An aquarium for armored catfish should be well-structured and equipped with many hiding places, Photo: Ingo Seidel<\/span><\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”2_5,3_5″ admin_label=”row” module_class=”bilddrehen” _builder_version=”4.27.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” global_colors_info=”{}”][et_pb_column type=”2_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_image src=”https:\/\/www.ancistrus.at\/wp-content\/uploads\/2025\/11\/Ancistrus-sp.-Aquarienstamm-Jungfische-Ingo-Seidel-2-600×400.jpg” alt=”Ancistrus sp. "Aquarium strain", juveniles ” title_text=”Ancistrus sp. "Aquarium strain", juveniles ” url=”https:\/\/www.ancistrus.at\/en\/ancistrus\/ancistrus-sp-aquarium-strain\/” _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”][\/et_pb_image][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” link_option_url=”https:\/\/www.ancistrus.at\/en\/ancistrus\/ancistrus-sp-aquarium-strain\/” global_colors_info=”{}”]<\/p>\n

Ancistrus<\/em> sp. “Aquarium strain” also eat zucchini, Photo: Ingo Seidel <\/span><\/p>\n

[\/et_pb_text][\/et_pb_column][et_pb_column type=”3_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”0px|||||” global_colors_info=”{}”]<\/p>\n

2. The “Cleanup Crew” myth and incorrect feeding<\/h3>\n

One of the biggest misconceptions is the assumption that Ancistrus<\/em> feed exclusively on algae and do not need additional food. While bristlenose catfish do eat algae and biofilms, this is rarely sufficient in densely planted or newly set up tanks. In nature, their diet consists of biofilm, detritus, and plant matter, sometimes supplemented by small invertebrates. <\/p>\n

Those who keep bristlenose catfish in a community tank should specifically offer them plant-based food: sinking green food tablets, spirulina wafers, and vegetables such as cucumber, zucchini, bell pepper, or pumpkin. Additionally, protein-rich food (e.g., brine shrimp, fine frozen food) can be offered occasionally, without permanently “fattening” the animals. <\/p>\n

An unbalanced, insufficient diet leads to Ancistrus<\/em> becoming emaciated, increasingly grazing on delicate plants, or intensifying their search for food at night and bothering other fish. Therefore, feeding errors are often the real cause when bristlenose catfish suddenly “cause problems.”[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”3_5,2_5″ admin_label=”row” module_class=”bildok” _builder_version=”4.27.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” custom_padding=”||||false|false” global_colors_info=”{}”][et_pb_column type=”3_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”0px|||||” global_colors_info=”{}”]<\/p>\n

3. Too many males and insufficient caves<\/h3>\n

Ancistrus<\/em> are cave spawners, and adult males vigorously defend their chosen caves. Therefore, in small community tanks, only one male or a harmonious pair should be kept. Multiple males usually only work in very well-structured, large tanks with many hiding places. <\/p>\n

Those who consciously keep Ancistrus<\/em> should always plan for sufficient caves: tubes, coconut shells, clay caves, or undercut roots are well-suited. It is important to have both smaller hiding places for juveniles and larger caves for adult males. A common mistake is to simply “let the catfish run along” without providing a single suitable cave \u2013 this contradicts their natural behavior.[\/et_pb_text][\/et_pb_column][et_pb_column type=”2_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_image src=”https:\/\/www.ancistrus.at\/wp-content\/uploads\/2025\/11\/es-sollten-zahlreiche-Laichroehren-angeboten-werden-Ingo-Seidel-600×400.jpg” alt=”numerous spawning tubes should be offered” title_text=”numerous spawning tubes should be offered” _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”][\/et_pb_image][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n

Male Ancistrus<\/em> need many hiding places, Photo: Ingo Seidel<\/span><\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”2_5,3_5″ admin_label=”row” module_class=”bilddrehen” _builder_version=”4.27.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” global_colors_info=”{}”][et_pb_column type=”2_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_image src=”https:\/\/www.ancistrus.at\/wp-content\/uploads\/2025\/11\/Apistogramma-ortegai-Papagei-Andreas-Tanke-600×400.jpg” alt=”Apistogramma ortegai "Parrot"” title_text=”Apistogramma ortegai "Parrot"” _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”][\/et_pb_image][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n

Apistogramma ortegai<\/i>, male, Photo: Andreas Tanke<\/span><\/p>\n

[\/et_pb_text][\/et_pb_column][et_pb_column type=”3_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”0px|||||” global_colors_info=”{}”]<\/p>\n

4. Incompatible Tank Mates and Unsuitable Water Parameters<\/h3>\n

Ancistrus<\/em> are considered tolerant of various water parameters and are well-suited for many typical community tank fish. Nevertheless, there are limits: very hard, extremely alkaline, or persistently heavily polluted aquariums also stress robust bristlenose catfish. Long-term proven conditions include temperatures around 23-27 \u00b0C, a pH value in the slightly acidic to neutral range, and moderate general hardness. However, there are also highly specialized species that originate primarily from very low-germ blackwater or from higher mountain regions. Therefore, one should thoroughly inquire about the requirements of the respective species. <\/p>\n

Tankmates that prey on the catfish or displace them from food are particularly problematic. Very large cichlids, predatory catfish, or highly territorial bottom-dwelling fish are not a good combination with Ancistrus<\/em>. Many bristlenose catfish also do not feel comfortable in the long run in “discus tanks” with extremely warm water and very little structure; however, dwarf cichlids of the genus Apistogramma are excellently suited for cohabitation. <\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”3_5,2_5″ admin_label=”row” module_class=”bildok” _builder_version=”4.27.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” global_colors_info=”{}”][et_pb_column type=”3_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”0px|||||” global_colors_info=”{}”]<\/p>\n

5. Unplanned reproduction and overpopulation of offspring<\/h3>\n

Another common mistake is underestimating the reproductive enthusiasm of Ancistrus<\/em>. If suitable caves are available and the fish are well-fed, it is not uncommon for regular clutches of several dozen eggs to occur. The male takes over brood care, guarding the cave and fanning the eggs. <\/p>\n

In a small community tank, such reproduction can quickly lead to an oversupply of juveniles. Even if other fish decimate some of the fry, often enough young catfish remain to overpopulate the tank. This is especially true for the widespread form Ancistrus<\/em> sp. “Aquarium strain” <\/a> is a very good example of this. In this case, caves are often not even necessary for reproduction. <\/p>\n

[\/et_pb_text][\/et_pb_column][et_pb_column type=”2_5″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_image src=”https:\/\/www.ancistrus.at\/wp-content\/uploads\/2025\/11\/Ancistrus-sp.-Aquarienstamm-Maennchen-Ingo-Seidel-2-600×400.jpg” alt=”Ancistrus sp. "Aquarium strain", male ” title_text=”Ancistrus sp. "Aquarium strain", male ” url=”https:\/\/www.ancistrus.at\/en\/ancistrus\/ancistrus-sp-aquarium-strain\/” _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”][\/et_pb_image][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” link_option_url=”https:\/\/www.ancistrus.at\/en\/ancistrus\/ancistrus-sp-aquarium-strain\/” global_colors_info=”{}”]<\/p>\n

Ancistrus<\/em> sp. “Aquarium strain”, male in glass as a cave, Photo: Ingo Seidel <\/span><\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row admin_label=”row” _builder_version=”4.27.4″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”0px|||||” global_colors_info=”{}”]<\/p>\n

Conclusion: Consciously Keeping Ancistrus<\/em> in a Community Tank<\/h3>\n

Bristlenose catfish are great aquarium inhabitants if their needs are taken seriously: sufficient space, structure, and caves, a balanced diet, suitable tankmates, and a thoughtful approach to reproduction. Then Ancistrus<\/em> will not become a “problem fish” but will enrich the community tank with their interesting behavior and their usefulness as biofilm grazers. <\/p>\n

For those who want to delve deeper into the world of Ancistrus catfish, the bilingual standard work “Antennenwelse: The Armored Catfish of the Genus Ancistrus”<\/a> provides detailed information on keeping, biology, biodiversity, and L-numbers. The book is available at the ATS-Aquashop<\/a>, among other places, and ideally complements the content of Ancistrus.at.<\/p>\n

If you would like to delve deeper into the basics, take a look at our article on keeping Ancistrus catfish in the aquarium<\/a>. You can find an overview of described and undescribed forms in the Ancistrus species list<\/a>.<\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”3_5,2_5″ _builder_version=”4.27.4″ _module_preset=”default” background_color=”RGBA(255,255,255,0)” width=”100%” custom_padding=”2vh|3vw|5vh|0vw|false|false” border_color_all=”#E7E7E7″ global_colors_info=”{}”][et_pb_column type=”3_5″ _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”|1vw||1vw|false|true” global_colors_info=”{}”][et_pb_cta title=”More Knowledge on Keeping Ancistrus” button_url=”https:\/\/www.ats-aquashop.de\/Antennenwelse-Die-Harnischwelse-der-Gattung-Ancistrus” button_text=”View Book in ATS-Aquashop” _builder_version=”4.27.4″ _module_preset=”default” header_text_color=”#293133″ body_text_color=”#293133″ background_color=”#E7E7E7″ background_layout=”light” link_option_url=”https:\/\/www.ats-aquashop.de\/Antennenwelse-Die-Harnischwelse-der-Gattung-Ancistrus” box_shadow_style=”preset6″ box_shadow_horizontal=”6px” box_shadow_vertical=”6px” box_shadow_color=”rgba(231,231,231,0.67)” global_colors_info=”{}”]Those who want to truly care for their bristlenose catfish appropriately, rather than just “letting them run along,” will find detailed information on species, L-numbers, and biology in the standard work “Bristlenose Catfish: The Armored Catfish of the Genus Ancistrus”<\/a>.[\/et_pb_cta][\/et_pb_column][et_pb_column type=”2_5″ _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}”][et_pb_image src=”https:\/\/www.ancistrus.at\/wp-content\/uploads\/2025\/04\/Cover_AncistrusBuch-scaled.jpg” title_text=”Ancistrus Book Cover” url=”https:\/\/www.ats-aquashop.de\/Antennenwelse-Die-Harnischwelse-der-Gattung-Ancistrus” url_new_window=”on” _builder_version=”4.27.4″ _module_preset=”default” transform_rotate=”0deg|0deg|2deg” box_shadow_style=”preset2″ box_shadow_horizontal=”18px” box_shadow_vertical=”13px” box_shadow_spread=”12px” box_shadow_color=”rgba(0,0,0,0.5)” global_colors_info=”{}”][\/et_pb_image][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":"

Bristlenose catfish of the genus Ancistrus are among the most popular armored catfish in aquaristics. They remain relatively small, usually 10-13 cm, eat algae and biofilm, and are considered robust aquarium fish found in many community tanks. Nevertheless, Ancistrus are often underestimated in daily practice \u2013 leading to typical keeping mistakes that can result in […]<\/p>\n","protected":false},"author":1,"featured_media":2913,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[31,30],"tags":[],"class_list":["post-2900","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-care","category-general-information"],"_links":{"self":[{"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/posts\/2900","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/comments?post=2900"}],"version-history":[{"count":20,"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/posts\/2900\/revisions"}],"predecessor-version":[{"id":3235,"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/posts\/2900\/revisions\/3235"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/media\/2913"}],"wp:attachment":[{"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/media?parent=2900"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/categories?post=2900"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ancistrus.at\/en\/wp-json\/wp\/v2\/tags?post=2900"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}